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2011 AAHA Canine vaccine guidelines

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VETERINARY PRACTICE GUIDELINES
2011 AAHA
Canine Vaccination Guidelines*
y
Members of the American Animal Hospital Association (AAHA) Canine Vaccination Task Force:
Link V. Welborn, DVM, DABVP (Chairperson), John G. DeVries, DVM, DABVP, Richard Ford, DVM, MS, DACVIM,
(Hon)ACVPM, Robert T. Franklin, DVM, DACVIM, Kate F. Hurley, DVM, MPVM, Kent D. McClure, DVM, JD,
Michael A. Paul, DVM, Ronald D. Schultz, PhD, DACVM
Introduction
The previous versions of the American Animal Hospital Associ-
ation (AAHA) Canine Vaccine Guidelines, published in 2003 and
2006, and updated in 2007, represented a collaborative effort by
academicians, private practitioners, and industry to facilitate
efforts of veterinarians in the United States (US) and Canada in
making decisions regarding the selection and use of canine vac-
cines. Vaccination guidelines for shelter-housed dogs were also
included in 2006. Since that time, new canine vaccines have been
licensed, others have been withdrawn, and new information on
existing vaccines has led to the revision of current recom-
mendations. The 2011 AAHA Canine Vaccination Guidelines offer
a comprehensive review of canine vaccines currently available in
North America, updated recommendations on administration of
core versus noncore vaccines, and revised recommendations for
vaccination of shelter-housed dogs. Also included are updated
recommendations on serologic testing as a means of documenting
and monitoring immune responses to vaccines, an expanded
discussion on vaccine adverse events (AEs), and an updated review
of the legal implications associated with administering vaccines in
clinical practice.
The reader is reminded that scientic studies and refereed
journal publications are not available to support all of the
vaccination recommendations included within this document.
Some recommendations are based on unpublished studies,
current knowledge of immunology, and the experience of
experts in the eld. To that point, the reader is referred to a new
section of the AAHA Canine Vaccination Guidelines, entitled
Frequently Asked Questions (FAQs). Within this section, the
Task Force addresses several topical and controversial canine
vaccination issues posed by practicing veterinarians. The section
is subdivided into four categories to address questions on Ad-
ministration of Vaccines, Vaccine Products, Adverse Reactions
to Vaccines, and Legal Issues related to administration of vac-
cines, and is intended to provide additional advice on key
points of concern where scientic documentation may not be
available.
The AAHA Canine Vaccination Task Force developed the
2011 Guidelines in a manner consistent with best vaccination
practices. The Guidelines include expert opinion supported by
scientic study and encompass all canine vaccines currently
licensed in the US and Canada. The Guidelines include rec-
ommendations that may differ from statements on product
labels and product literature, especially with respect to initial
vaccination and revaccination (booster) intervals. It is the view of
the Task Force that veterinarians have considerable latitude in the
selection and use of veterinary biologic products licensed for
dogs, with rabies vaccine being a noted exception, and that these
Guidelines, although not intended to dictate an exclusive pro-
tocol or standard, do meet accepted standards of professional
practice.
This document was developed by AAHA through a collabo-
rative effort among Task Force members to aid practitioners in
making decisions about appropriate care of their canine patients
with respect to currently available vaccines. The Task Force
included experts in immunology, infectious diseases, internal
medicine, law, and clinical practice.
The Guidelines are supported by professional, scientic,
and clinical evidence, as well as published and unpublished
documentation.
These Guidelines and recommendations should not be
construed as dictating an exclusive protocol, course of treat-
ment, or procedure. Variations in practice may be warranted
based on the needs of the individual patient, resources, and
* These guidelines were sponsored by a generous educational grant from
Boehringer Ingelheim Vetmedica Inc., Merck Animal Health, Merial, and
Pfizer Animal Health.
y
Reviewers were provided by the American College of Veterinary Micro-
biologists.
ª2011 by American Animal Hospital Association JAAHA.ORG 1
limitations unique to each individual practice setting. The
Guidelines are not intended to be an AAHA standard of
care.
TABLE OF CONTENTS
Acronyms and Terms
Part 1: Canine Vaccination in Veterinary Practice
Vaccine Types
Vaccine Licensure
United States
Canada
Serologic Testing to Determine and Monitor Immunity
Interpreting Results of Serologic Tests
Applications of Serologic Testing
Application of Serology to Evaluate Duration of
Immunity
Vaccine Adverse EventsRecognition and Response
What Constitutes a Vaccine Adverse Event?
How to Report a Known or Suspected Adverse Event
Managing Adverse Event Risk in Individual Patients.
Canadian Food Inspection Agency
Patients with a Known or Suspected Vaccine Adverse Event
History
Small Breed Dogs
Law Considerations
Professional Discretion in the Use of Vaccines
Potential for Liability Associated with Vaccine
Administration
Consent Versus Informed Consent
Medical Record Documentation
Part 2: Vaccination of Shelter-Housed Dogs
Denition of a Shelter Environment
General Vaccination Guidelines for Shelters
Core Vaccines
Noncore Vaccines
Vaccines Not Recommended for Use in the Shelter
Environment
Dogs with a Documented Vaccination History at Time of
Admission
Vaccination of Long-Term Shelter-Housed Dogs
Vaccination of Pregnant Dogs
Vaccination of Sick Dogs
Appendix
Adverse Event Report Form (United States)
Adverse Event Report Form (Canada)
Frequently Asked Questions
Additional Reading
References
Acronyms and Terms
Regulatory Agency Acronyms
AMDUCA Animal Medicinal Drug Use Clarication Actapplies
only to animal drugs regulated by FDA, not veterinary biologics
regulated by USDA; APHIS Animal and Plant Health Inspec-
tion Servicean agency of the USDA;CFIA Canadian Food
Inspection Agencythe agency responsible for licensing veteri-
nary vaccines made and/or used in Canada;CVB Center for
Veterinary Biologics;FDA Food and Drug Administration
licenses all human vaccines and veterinary pharmaceuticals;
USDA United States Department of Agriculturelicenses all
veterinary vaccines
Vaccine Terms and Acronyms
Avirulent live attenuated bacterial vaccine;bacterin whole
killed cell bacterial vaccine; killed antigen inactivated vaccine
antigen (viral or bacterial); infectious vaccines vaccines that
infect the hosts cells to induce a protective immune response (e.g.,
modied-live [attenuated] viral vaccines [see text for specic
examples]); noninfectious vaccine vaccines that are incapable
of infecting host cells to produce additional antigen (e.g., killed
[inactivated] vaccines [see text for specic examples]); rrecombinant
vaccine antigenthis notation generally precedes the name of the
vaccine (e.g., recombinant canine distemper virus [rCDV]); sub-
unit vaccine a vaccine produced using conventional or recombi-
nant technology that contains specic subunits rather than a
complete virus or bacteria; viral vector a live nonpathogenic (or
attenuated) virus in which selected DNA or RNA of a pathogenic
virus is recombined for purposes of vaccine development; virus
vectored vaccines represent one form of recombinant vaccine
technology.
AAHA American Animal Hospital Association; AE adverse
event; Bb Bordetella bronchiseptica; CAV-1 canine adenovirus, type 1
(cause of canine viral hepatitis); protection from CAV-1 infection
is provided by parenterally administered CAV-2 vaccine; CAV-2
canine adenovirus, type 2; CCoV canine coronavirus cause of enteric
coronavirus infection (antigenically distinct from the canine re-
spiratory coronavirus [CRCoV]); CDV canine distemper virus; CIV
canine inuenza virusH3N8; CPiV canine parainuenza virus;
CPV-2 canine parvovirus, type 2; DOI duration of immunity; HI
hemagglutination inhibitiona laboratory technology used to
measure antibody levels (e.g., parvovirus antibody); HOD hyper-
trophic osteodystrophy; IgG immunoglobulin Ga class of humoral
antibody; most common type associated with immune response to
parenteral vaccine; also the most common class of antibody measured
as serum titers; IgM immunoglobulin Ma class of antibody, gen-
erally short lived and associated with early infection and initial
2JAAHA | 47:5 Sep/Oct 2011
vaccination; IM intramuscular (route of administration); IN in-
tranasal or mucosal (route of administration); MDA maternally
derived antibody; MLV modied live virus, attenuated virus vaccine;
MV measles virus; NSAIDs nonsteroidal anti-inammatory drugs;
OMC outer membrane componentused in reference to bacterial
surface proteins (subunit antigens) in selected bacterins; also referred
to as conventionalsubunit vaccines; OspA outer surface protein
A(antigen)ofBorrelia burgdorferi;OspC outer surface protein
C(antigen)ofBorrelia burgdorferi;PCR polymerase chain
reactiona very sensitive test that measures the presence or
amount of RNA or DNA of a specic organism; RV rabies virus;
SAE serious adverse event; sIgA secretory immunoglobulin A
a class of antibody, most commonly associated with a local (mucosal)
immune response after IN vaccination; SQ subcutaneous (route of
administration); US United States; VN virus neutralizationalabo-
ratory technology used to measure antibody levels (e.g., canine
distemper antibody)
Part I: Canine Vaccination in
General Veterinary Practice
Vaccines provide proven life-saving benets, are associated with
minimal risk, and should be part of routine preventative health
care. Life stage and lifestyle, risk of exposure, and underlying
medical conditions should all be considered when developing
a vaccination protocol.
Vaccine Types
Over the last 5 decades, signicant advances in vaccine tech-
nology have resulted in many types of biologicals (vaccines) being
licensed by the U.S. Department of Agriculture (USDA) and
Canadian Food Inspection Agency (CFIA) for use in dogs. The
two general types of vaccines now available include the non-
infectious (inactivated, killed, dead, conventional and recombi-
nant subunit, plasmid DNA, and avenomous) vaccines and the
infectious (attenuated, avirulent, modied live, recombinant viral
vectored) vaccines.
14
The availability of a wide variety of
products provides veterinarians with multiple options when
selecting and administering core and noncore vaccines. The
following section provides a summary of the theory and tech-
nology behind the different types of canine vaccines currently on
the market.
Noninfectious (Inactivated, Killed) Vaccines
The noninfectious (inactivated, killed) vaccines include killed
viral (e.g., rabies virus [RV], canine inuenza virus [CIV], and
canine coronavirus [CCoV]), whole killed cell bacterins (certain
Lyme, Leptospira), bacterial subunit (recombinant outer surface
protein A [OspA] Lyme, and conventional subunit Leptospira outer
membrane component [OMC] vaccines), a cellular antigen ex-
tract of the Bordetella bronchiseptica (Bb) vaccine, and Western
diamondback rattlesnake avenomous vaccine (Table 1). As the
name noninfectiousimplies, these vaccines do not infect the
host to produce new antigen. Thus, they must contain adequate
amounts of antigen to immunize. Because the antigen alone
may not be adequate to immunize a dog, many of the non-
infectious vaccines must also contain adjuvant. Adjuvants in-
clude a wide variety of substances that maintain or depot the
antigenaswellasstimulateaninammatory response to pro-
vide a more robust immune response to the vaccine antigens.
5,6
This increased nonspecic stimulation of the immune system
caused by adjuvants is required to induce a protective response
to antigens. Some of the killed whole cell bacterial vaccines do
not require the addition of adjuvant because the bacterial cell
walls or portions of cell wall (e.g., lipopolysaccharide, pepti-
doglycans) of Bordetella,Leptospira,orBorrelia have adjuvant
properties, in addition to serving as antigens.
5,6
Together, the
antigen and adjuvant are designed to stimulate a protective im-
mune response.
Critical to production of a noninfectious vaccine is the
process used to inactivate the virus or bacteria, to ensure that it
is dead. At the same time, this process must not signicantly
alter the antigenic properties of the organism. Chemicals,
ionizing irradiation, and other methods are used to kill the
organisms. Chemicals used for inactivation include formalin,
b-propiolactone, ethylenediamine, and other agents. Some of
these agents cannot be completely eliminated from the nal
product. Injection site pain or hypersensitivity have sometimes
been attributed to the residual chemicals.
7
When compared
with infectious (attenuated, avirulent, modied live, recombi-
nant viral vectored) vaccines, noninfectious vaccines are more
likely to produce local and systemic adverse reactions in some
dogs.
79
TheseAEscanbecausedbytheantigen(e.g.,virusor
bacteria), the adjuvant, serum or cellular proteins, or a com-
bination of vaccine components. Noninfectious vaccines are
more stable than infectious vaccines, as the microbial agents do
not need to remain viable (i.e., do not need to infect cells) to
immunize.
Noninfectious vaccines are often considered to be the safest
vaccine type because the immunizing agent (virus or bacteria) is
dead; thus, it cannot revert to virulence and cannot cause the
disease that the vaccine was intended to prevent.
110
However, it
should be understood that hypersensitivity reactions are more
common with the noninfectious vaccines than infectious vaccines;
thus, they may not be perceived to be as safe as the infectious
Veterinary Practice Guidelines
JAAHA.ORG 3
TABLE 1
2011 AAHA Canine Vaccination Guidelines* for the General Veterinary Practice
Vaccine
y
Initial Vaccination (,16 wk of age)
Initial Vaccination
(.16 wk of age)
Revaccination (Booster)
Recommendation Comments and Recommendations
CDV (MLV) or rCDV Puppies should be vaccinated every
3–4 wk between the ages of 6 and
16 wk (e.g., at 6, 10, and 14 wk, or
8, 12, and 16 wk). To minimize the
risk of maternal antibody interference
with vaccination, the final dose of the
initial series should be administered
between 14 and 16 wk of age,
regardless of the product used.
One dose is considered
protective and acceptable.
Revaccination is
recommended every $3yr
after completion of the
initial vaccination,
regardless of the
product used.
Dogs (puppies) completing the initial
vaccination series by 16 wk of age
or younger should receive a single
booster vaccination no later than
1 yr after completion of the initial
series and be revaccinated every
$3 yr thereafter, regardless of
the product used.
Core
·Among healthy dogs, all commercially
available distemper vaccines are
expected to induce a sustained
protective immune response lasting
at least $5yr.
·Among healthy dogs, the rCDV vaccine
has been shown to induce a protective
immune response lasting at least 5 yr.
·Although rare, some dogs are
genetically predisposed “nonresponders”
and are incapable of developing protective
immunity subsequent to CDV vaccination.
·The rCDV vaccine can be used
interchangeably with MLV-CDV vaccine.
·It is recommended that all CDV vaccines
be administered within 1 hr after
reconstitution; vaccine held .1 hr should
be discarded. MLV-CDV vaccine is
particularly vulnerable to inactivation
after reconstitution (rehydration).
MV (MLV–an aid in the
prevention of CDV infection
in puppies only) (Note:
measles antigen is currently
available in a 4-way
combined MLV vaccine: CDV 1
measles 1CAV-2 1CPiV)
and a 2-way combined MLV
vaccine: CDV 1Measles
IM route only
A single dose is recommended
for administration to healthy
dogs between the ages of
6 and 12 wk.
Not recommended Not recommended Noncore
·Measles vaccine is only intended to provide
temporary immunization of young puppies
against CDV. MV has been shown to
cross-protect puppies against CDV in
presence of MDA to CDV.
·These vaccines should not be administered
to dog ,6 wk or female dogs .12 wk of
age that will be used for breeding, as these
puppies may have maternally derived
measles antibody and will block MV induced
immunity.
·After administration of a single dose of
measles virus-containing vaccine, subsequent
vaccination with a CDV vaccine that does
not contain MV is recommended at 2–4 wk
intervals until the patient is 14–16 wk of age.
·Vaccine that contains MV must be
administered by the IM route.
·It is recommended that MV-containing
vaccine be administered within 1 hr after
reconstitution; vaccine held .1 hr should
be discarded.
(Table continues)
4JAAHA | 47:5 Sep/Oct 2011
TABLE 1 (continued )TABLE 1 (continued )
Vaccine
y
Initial Vaccination (,16 wk of age)
Initial Vaccination
(.16 wk of age)
Revaccination (Booster)
Recommendation Comments and Recommendations
CPV-2 (MLV) Puppies should be vaccinated
every 3–4 wk between the ages
of 6 and 16 wk (e.g., at 6, 10, and
14 wk, or 8, 12, and 16 wk).
To minimize the risk of maternal
antibody interference with
vaccination, the final
dose of the initial series should be
administered between 14 and
16 wk of age, regardless of the
product used.
One dose is considered
protective and acceptable.
Revaccination is
recommended every
$3 yr after completion
of the initial vaccination,
regardless of the
product used.
Dogs (puppies) completing the initial
vaccination series by #16 wk of
age should receive a single
booster vaccination not later
than 1 yr after completion of
the initial series and be
revaccinated every $3yr
thereafter, regardless of the
product used.
Core
·All MLV-CPV-2 vaccines available today
are expected to provide immunity from
disease caused by any field variant
recognized today (CPV-2a, -2b, and -2c).
·As new variants of CPV-2 occur, those
variants will need to be evaluated, as
the previous ones have, to ensure
vaccines in use at the time are protective.
·Among healthy dogs, all commercially
available MLV-CPV-2 vaccines are
expected to induce a sustained protective
immune response lasting at least 5 yr.
·Although rare, some dogs are genetic
nonresponders and are incapable of
developing protective immunity
subsequent to CPV-2 vaccination no
matter how often vaccine is administered.
·Today, specific breed-susceptibility to
CPV-2 nonresponsiveness is not
recognized. There is no value in
extending initial CPV-2 vaccination series
beyond 16 wk of age.
·It is recommended that CPV-2 vaccine,
especially when administered in
combination with CDV vaccine, be
administered within 1 hr after
reconstitution; vaccine held .1hr
should be discarded.
CAV-2 (MLV parenteral) Puppies should be vaccinated every
3–4 wk between the ages of 6 and
16 wk (e.g., at 6, 10, and 14 wk,
or 8, 12, and 16 wk). To minimize
the risk of maternal antibody
interference with vaccination,
the final dose of the initial
series should be administered
between 14 and 16 wk of age,
regardless of the product used.
One dose is considered
protective and acceptable.
Revaccination is
recommended every $3yr
after completion of the
initial vaccination,
regardless of the
product used.
Dogs (puppies) completing the initial
vaccination series by #16 wk
of age should receive a single
booster vaccination not later than
1 yr after completion of the
initial series and be revaccinated
every $3 yr thereafter,
regardless of the product used.
Core
·CAV-2 induces protection against CAV-1
(canine hepatitis virus) as well as CAV-2
(one of the agents known to be associated
with canine infectious respiratory disease).
·Among healthy dogs, all commercially
available MLV-CAV-2 vaccines are
expected to induce a sustained protective
immune response lasting at least 7 yr.
·It is recommended that CAV-2 vaccine,
especially when administered in combination
with CDV vaccine, be administered within 1 hr
after reconstitution; vaccine held .1hr
should be discarded.
(Table continues)
Veterinary Practice Guidelines
JAAHA.ORG 5
TABLE 1 (continued )
Vaccine
y
Initial Vaccination (,16 wk of age)
Initial Vaccination
(.16 wk of age)
Revaccination (Booster)
Recommendation Comments and Recommendations
Rabies 1 yr (killed) Administer a single dose not earlier
than 12 wk of age or as required
by state, provincial, and/or local
requirements.
Administer a single dose
of a “1-yr” rabies vaccine.
Administer a single dose of a“1-yr”
rabies vaccine annually.
State, provincial, and/or local laws
apply.
Core
·State, provincial, and local statutes govern
the frequency of administration for
products labeled as “1-yr” rabies vaccine.
·Route of administration may not be
optional; see product literature for details.
Rabies 3 yr (killed) Administer a single dose of a “3-yr”
rabies vaccine not earlier than
12 wk of age or as required
by state, provincial, and/or
local requirements.
Administer a single dose of
a “3-yr” rabies vaccine
or as required by state,
provincial, and/or local
requirements.
Administer a single dose of a “3-yr”
rabies vaccine within 1 yr after
administration of the initial dose,
regardless of the animal’s age
at the time the initial dose was
administered. Subsequently,
revaccination with a “3-yr rabies”
vaccine should be administered
every 3 yr thereafter, unless
state, provincial, and/or local
requirements stipulate otherwise.
Core
·State, provincial, and local statutes
govern the frequency of administration
for products labeled as “3-yr rabies”
vaccines.
·Use of rabies vaccine multidose (“tank”)
vials in companion animals is not
recommended.
·Route of administration may not be
optional; see product literature for details.
CPiV (MLV) For parenteral
administration only. (Available
only as a combined product
for parenteral administration)
Parenteral CPiV vaccine is only available
in combination with core vaccines
(CDV-CPV-2 and CAV-2). Therefore,
veterinarians who elect to administer
parenteral CPiV vaccine should
follow the same administration
recommendations as outlined
above for the core vaccines.
Veterinarians who elect to
administer parenteral
CPiV vaccine should
follow the same
administration
recommendations as
outlined above for the
core vaccines.
Veterinarians who elect to
administer parenteral CPiV
vaccine should follow the
same administration
recommendations as outlined
above for the core vaccines.
Noncore
·Parenterally administered CPiV vaccine
does prevent clinical signs but has not
been shown to prevent infection
and shedding.
·Use of the parenteral vaccine is
recommended for use in those patients
that aggressively resist IN vaccination.
Bb (inactivated-cellular antigen
extract)
For parenteral administration
only.
Administer first dose at 8 wk of age and
second dose at 12 wk of age (see
comments).
Two doses, 2–4 wk apart
are required.
Annually Noncore
·There is no known advantage to
administering parenteral and IN Bb
vaccines simultaneously.
·On initial vaccination, administration
should be scheduled such that the
second dose can be administered at
least 1 wk before exposure (kennel,
dog show, daycare, etc).
·The parenteral vaccine is not
immunogenic if administered by
the IN route.
Bb (live avirulent bacteria)
For IN administration
only.
A single dose should be administered in
conjunction with 1 of the core vaccine
doses. Note: The initial IN dose may
be administered to dogs as young
as 3–4 wk of age (depending on
manufacturer) when exposure
risk is considered to be high
(see comments).
A single dose is
recommended.
Annually or more often in
high-risk animals.
Noncore
Transient (3–10 days) coughing, sneezing,
or nasal discharge may occur in a small
percentage of vaccinates.
IN Bb vaccine must not be administered
parenterally.
(Table continues)
6JAAHA | 47:5 Sep/Oct 2011
TABLE 1 (continued )TABLE 1 (continued )
Vaccine
y
Initial Vaccination (,16 wk of age)
Initial Vaccination
(.16 wk of age)
Revaccination (Booster)
Recommendation Comments and Recommendations
CPiV (MLV) For IN administration
only. (IN CPiV vaccine is
only available in combination
with IN Bb vaccine or
Bb 1CAV-2)
A single dose should be administered in
conjunction with 1 of the core vaccine
doses. Note: The initial IN dose
may be administered to dogs as young
as 3–4 wk of age (depending on
manufacturer) when exposure risk is
considered to be high (see comments).
A single dose is
recommended.
Annually or more often
in high-risk animals.
Noncore
·When feasible, IN vaccination is
recommended over parenteral
vaccination. Parenterally administered
CPiV vaccine does prevent clinical
signs, but has not been shown to
prevent infection and shedding. IN
CPiV vaccine prevents not only clinical
disease but also infection and viral
replication (shedding).
CAV-2 (MLV) (for IN
administration only)
(Available only in
combination with IN Bb
and CPiV vaccine)
A single dose should be administered in
conjunction with 1 of the core vaccine
doses. Note: The initial IN dose may
be administered to dogs as young
as 3–4 wk of age (depending on
manufacturer) when exposure risk
is considered to be high
(see comments).
A single dose is
recommended.
Annually or more often
in high-risk animals.
Noncore
·Administration of IN CAV-2 vaccine is
recommended for use in dogs
considered at risk for respiratory
infection caused by the CAV-2 virus.
·IN CAV-2 vaccine may not provide
protective immunity against CAV-1
(canine hepatitis virus) infection and
should not be considered a replacement
for parenteral MLV-CAV-2 vaccination.
Canine influenza vaccine
(killed virus)
Administer 1 dose not earlier than 6 wk
of age and a second dose 2–4 wk
later.
Two doses, 2–4 wk apart are
required. A single initial
dose will not immunize a
seronegative dog.
Annually Noncore
Borrelia burgdorferi (Lyme
disease) (killed whole
cell bacterin) or
Borrelia burgdorferi
(rLyme: rOspA)
Administer 1 dose not earlier than
12 wk of age and a second
dose 2–4 wk later. For optimal
response, do not administer to
dogs ,12 wk of age.
Two doses, 2–4 wk apart. A
single initial dose will not
immunize a seronegative dog.
Annually. Alternatively, it has been
recommended that initial
vaccination or revaccination
(booster) be administered
before the beginning of tick
season, as determined
regionally.
Noncore
·Generally recommended only for use in
dogs with a known risk of exposure,
living in or visiting regions where the
risk of vector tick exposure is considered
to be high, or where disease is known to
be endemic.
·In addition to vaccination, prevention of
canine Lyme borreliosis includes regular
utilization of tick control products.
Leptospira interrogans (4-way
killed whole cell or subunit
bacterin) Contains serovars
canicola 1icterohemorrhagiae 1
grippotyphosa 1pomona
Administer 1 dose not earlier than
12 wk of age and a second
dose 2–4 wk later. For optimal
response, do not administer to
dogs ,12 wk of age.
Two doses, 2–4 wk apart. A
single initial dose will not
immunize a seronegative
dog.
Annually. Administration of booster
vaccines should be restricted to
dogs with a reasonable risk of
exposure.
Noncore
·Specific vaccination recommendations
vary on the basis: (1) known geographic
occurrence/prevalence, and (2) exposure
risk in the individual patient.
·It is recommended that the first dose
of leptospira vaccine be delayed until
12 wk of age.
·DOI based on challenge studies has
been shown to be approximately 1 yr.
(Table continues)
Veterinary Practice Guidelines
JAAHA.ORG 7
TABLE 1 (continued )
Vaccine
y
Initial Vaccination (,16 wk of age)
Initial Vaccination
(.16 wk of age)
Revaccination (Booster)
Recommendation Comments and Recommendations
Leptospira interrogans (2-way
killed bacterin) Contains
serovars canicola 1
icterohemorrhagiae only
Intentionally left blank Intentionally left blank Intentionally left blank Not recommended
Canine oral melanoma (plasmid
DNA vaccine-expresses human
tyrosinase). Availability is
currently limited to practicing
oncologists and selected
specialists.
Not applicable. See Manufacturer’s
indications for use.
See Manufacturer’s
indications for use.
See Manufacturer’s indications
for use.
Use of this vaccine is limited to the treatment
of dogs with malignant melanoma.
·This vaccine aids in extending survival times
of dogs with Stage II or III oral melanoma
and for which local disease control has
been achieved (negative local lymph nodes
or positive lymph nodes that were surgically
removed or irradiated). The human tyrosinase
protein will stimulate an immune response
that is effective against canine melanoma
cells that over express tyrosinase.
·Vaccination is not indicated for the
prevention of canine melanoma.
Crotalus atrox (Western
Diamondback rattlesnake
vaccine) (toxoid)
Initial vaccination recommendation
may depend on size of the
individual dog. Refer to
manufacturer’s label. Current
recommendations are to
administer 2 doses, 1 mo apart,
to dogs as young as 4 mo.
Initial vaccination
recommendation may
depend on size of the
individual dog. Refer to
manufacturer’s label.
Current recommendations
are to administer 2 doses
1 mo apart.
Refer to manufacturer’s label.
Annual revaccination
requirements vary depending
on prior exposure, size of
dog, and risk of exposure.
Refer to manufacturer’s label.
Field efficacy and experimental challenge
data in dogs are not available at this time.
·Intended to protect dogs against the
venom associated with the bite of the
Western Diamondback rattlesnake.
Some cross-protection may exist
against the venom of the Eastern
Diamondback rattlesnake. There is
currently no evidence of cross-protection
against the venom (neurotoxin) of the
Mojave rattlesnake.
·Vaccine efficacy and dose
recommendations are based on toxin
neutralization studies conducted in mice.
Conventional challenge studies in dogs
have not been conducted. Neither
experimental nor field data are currently
available on this product.
Note: Veterinarians should advise clientele
of vaccinated dogs that vaccination does not
eliminate the need to treat individual
dogs subsequent to envenomation.
Canine coronavirus
(CCoV) (killed
and MLV)
Intentionally left blank Intentionally left blank Intentionally left blank Not recommended
·Neither the MLV vaccine nor the
killed CCoV vaccines have been
shown to significantly reduce disease
caused by a combination of CCoV and
CPV-2. Only CPV-2 vaccines have been
shown to protect dogs against a
dual-virus challenge.
(Table continues)
8JAAHA | 47:5 Sep/Oct 2011
vaccines.
11
In general, all canine vaccines are quite safe and only
a small percentage of vaccinated dogs, regardless of type of vac-
cine, develop severe adverse reactions.
1224
Vaccine Stability
Because the antigenic bacteria or virus used in noninfectious
(killed) vaccine is incapable of replicating, killed vaccines are
prepared and sold as an aqueous (liquid) product that can be
directly administered to the patient. During storage, non-
infectious vaccines are highly stable. Although refrigeration is
recommended, noninfectious vaccines are signicantly less
susceptible to heat inactivation than infectious vaccines. Non-
infectious vaccines can, however, be denatured. If exposed to
chemicals (e.g., rewashed, reused syringes), a noninfectious vaccine
could become ineffective. Therefore, sterile, unused syringes should
be used when administering vaccines. Noninfectious vaccines
should be administered before the expiration date printed on the
vial.
Both infectious and noninfectious vaccines are important
and required in every canine vaccination program. However,
it is important not to mix noninfectious vaccines with infec-
tious vaccines in the same syringe, unless specied by the
manufacturer.
14,1924
Multiple Dose Vials
Multiple dose, also called tankvials, of killed rabies vaccine
are available. Typically prepared in 10 mL (10 dose) vials,
theseproductsshouldonlybeusedforhighvolumevaccina-
tion clinics or by shelter immunization programs where large
numbers of dogs are vaccinated over a short period of time
(same day). Multiple dose vials require multiple needle pen-
etrations over time, thereby increasing the risk for contami-
nation. Tank vials should be shaken frequently to ensure the
concentration of antigen/adjuvant is consistent among doses
withdrawn from a single vial. Single-dose vials are available
and are strongly recommended for use in general veterinary
practice.
Routes of Administration
Because noninfectious canine vaccines cannot infect or replicate,
they must be administered parenterally (subcutaneously [SQ] or
intramuscularly [IM]); noninfectious vaccine should not be ad-
ministered directly onto mucosal surfaces (e.g., intranasal [IN]
administration). Noninfectious canine vaccines stimulate primarily
systemic humoral immunity (immunoglobulin-M [IgM] and -G
[IgG]) with limited or no cell mediated immunity, depending on the
antigen and the adjuvant.
11,24
TABLE 1 (continued )TABLE 1 (continued )
Vaccine
y
Initial Vaccination (,16 wk of age)
Initial Vaccination
(.16 wk of age)
Revaccination (Booster)
Recommendation Comments and Recommendations
·DOI has never been established. In
controlled challenge studies, neither
vaccinates nor control dogs developed
clinical evidence of disease after
experimental virus challenge.
* The AAHA 2011 Canine Vaccine Guidelines are provided to assist veterinarians in developing a vaccination protocol for use in clinical practice. They are not intended to represent vaccination standards for all dogs nor are
they intended to represent a universal vaccination protocol applicable for all dogs.
z
Route of administration is SQ (subcutaneous) or IM (intramuscular) unless otherwise noted by the manufacturer.
Bb, Bordetella bronchiseptica; CAV-1, canine adenovirus, type 1 (cause of canine viral hepatitis); protection from CAV-1 infection is provided by parenterally administered CAV-2 vaccine; CAV-2, canine adenovirus, type 2;
CCoV, canine coronavirus cause of enteric coronavirus infection (antigenically distinct from the canine respiratory coronavirus [CRCoV]); CDV, canine distemper virus; CIV, canine influenza virus—H3N8; CPiV, canine
parainfluenza virus; CPV-2, canine parvovirus, type 2; DOI, duration of immunity; IN, intranasal; MLV, modified live virus, attenuated virus vaccine; MV, measles virus; OspA outer surface protein A (antigen) of Borrelia
burgdorferi; RV, rabies virus.
Veterinary Practice Guidelines
JAAHA.ORG 9
The canine oral melanoma vaccine is a noninfectious re-
combinant (DNA) vaccine licensed for needle-free transdermal
administration only. It is currently the only vaccine licensed for
transdermal administration in dogs.
Initial Vaccination
Most noninfectious vaccines require at least two initial doses to
immunize, regardless of the dogs age.
1,14,25,26
The rst dose of
a noninfectious vaccine generally primes the immune response
and the second dose, which should be administered 26wk
later, provides the protective immune response. Immunity
typically develops approximately 7 days after the second dose.
Therefore, the minimum time for onset of immunity is ap-
proximately 3 wk after administration of the rst dose of a
noninfectious vaccine.
When the interval between the initial two doses of a non-
infectious vaccine exceeds 6 wk, it is recommended the dog be
revaccinated, administering two doses, 26 wk apart, to ensure
protective immunity has developed.
Rabies vaccine is the obvious exception. Rabies vaccine an-
tigen is highly immunogenic. Throughout the US and Canada,
a single dose, administered at $12 wk of age, is considered to
induce protective immunity. It should be noted that the onset of
immunity after administration of the initial rabies vaccine may be
dened by applicable legal requirements.
Minimum Age at the Time of Initial Vaccination
Administration of a noninfectious vaccine to a dog ,12 wk of
age may be blocked by maternally derived antibody (MDA). A
seconddose,evenifgivenafter12wkofage,wouldnotbe
expected to immunize the patient (rabies being the exception).
To ensure that puppies are effectively immunized, it is rec-
ommended that the rst vaccine dose in the initial series of
most noninfectious (inactivated, killed) vaccines be adminis-
tered not earlier than 12 wk of age. Among orphans or those
puppies that are known not to have received colostrum, the
rst dose of a noninfectious vaccine may be administered as
early as 6 wk of age.
Immunization in the Presence of Maternally Derived Antibody
The mechanism whereby MDA interferes with noninfectious vac-
cine is different than that for infectious vaccine. Through a
mechanism known as antigen masking,MDA covers, or
masks,antigenic epitopes on the vaccine virus or bacteria that
are necessary to elicit a protective immune response. In an effort
to overcome MDA-induced interference with noninfectious vac-
cines, vaccine manufacturers can use a variety of methods.
including the addition of adjuvant as well as increasing the anti-
gen concentration in each dose of vaccine.
Because high titers of MDA specic for protective epitopes are
generally required to cause antigen masking,MDA interference
to most bacterins is uncommon after 69wkofage.However,
as noted previously, two doses of a noninfectious vaccine are
required to induce a protective immune response. If sufcient
MDA is present to interfere with the rst dose, the second dose
will not immunize. Therefore, it is recommended that the
earliest age for administering the rst dose of a noninfectious
vaccine be 12 wk. Also, it is recommended that the noninfectious
bacterins (e.g., Leptospira or Lyme) be given at $12 wk because the
immune system is more mature. Thus, it is more likely that a
protective immune response, rather than hypersensitive response,
will develop.
1
Onset of Immunity
After initial vaccination, the onset of protective immunity requires
more time to develop with noninfectious vaccines than with in-
fectious vaccines. With most noninfectious vaccines, the minimum
time from administration of the rst dose in the initial vaccination
series to development of protective immunity in a naïve dog is
3 wk (2 wk minimum interval between doses plus 1 wk for anti-
body production, for a minimum of 3 wk).
14
The immune (antibody) response after administration of a
single dose of a noninfectious vaccine in adult dogs that have been
vaccinated within the previous year is considered to be rapid
(hours to days) and protective.
The legally dened onset of immunity after administration of
the rst dose of a rabies vaccine is usually stipulated by state, local,
or provincial requirements. Because the dened interval between
the rabies vaccination and rabies immunization may vary among
states and within states, veterinarians are encouraged to contact
appropriate authorities regarding a specied onset of immunity
interval for rabies.
Missed DoseInitial Series
When administering a noninfectious vaccine for the rst time in
the life of a dog, at least two doses, administered 26 wk apart, is
recommended. If the interval between the rst two doses exceeds
6 wk, it is recommended that two additional doses be adminis-
tered at an interval of 26 wk, thereby insuring that both immune
priming and immunization occur.
Missed DoseAdult Booster
Because noninfectious vaccines generally have a duration of
immunity (DOI) that is shorter than infectious vaccines, annual
10 JAAHA | 47:5 Sep/Oct 2011
revaccination (booster) is commonly recommended. A dog
that failed to receive a noninfectious vaccine at the recom-
mended interval of 12 mo is unlikely to maintain protective
immunity for the same length of time (years) that occurs after
administration of infectious viral (core) vaccines. At some point
beyond 12 mo, administration of a single dose of a noninfec-
tious vaccine may fail to induce a protective immune response (due
to loss of immunologic memory); in such cases, administration
of two doses, 26 wk apart, may be required to immunize.
However, intervals dening when two doses versus one dose
would be required to immunize have not been established. Specic
intervals will vary, depending on: (1) the vaccine, (2) the patients
(intrinsic) immune response, (3) time elapsed since administra-
tion of the last dose, and (4) total lifetime doses the dog received.
The decision to revaccinate a dog with two doses versus one dose
is left to the discretion of the veterinarian.
The following general guidance is offered for dogs that are
overdue for a noninfectious vaccine and are considered to be at risk
for exposure.
·Leptospirosis: limited studies have been conducted to assess
immune response to a single dose of vaccine in dogs that have
not received a booster vaccination in .12 mo. Among dogs
with a high risk of exposure, it is reasonable to consider ad-
ministering two doses of vaccine, 26 wk apart, if the interval
between doses exceeds 24 mo.
14
·Lyme disease: only limited (unpublished) studies have been
performed to evaluate the immune response to a single dose
of vaccine in dogs that have not received a booster vaccination
in .12 mo. Although a single dose of Lyme vaccine given years
after the initial doses can raise antibody levels, the protective
quality of these antibodies has not been conrmed by challenge.
Among dogs with a high risk of exposure, it is reasonable to
consider administering two doses of vaccine, 26 wk apart, if
the interval between doses exceeds 24 mo.
27
·CIV: studies have not been performed to evaluate the immune
response to a single dose of vaccine in dogs that have not re-
ceived a booster vaccination in .12 mo. Among dogs having
a high risk of exposure, it is reasonable to consider administer-
ing two doses of vaccine, 26 wk apart, if the interval between
doses exceeds 36 mo.
·Rabies: revaccination with killed rabies vaccine in dogs that
exceeded the stipulated interval, 1 yr (initial two doses) or 3 yr
(revaccination), is dened by applicable legal requirements. In
most states, a dog that exceeded the dened interval for rabies
vaccination may receive a single dose of a 3 yr vaccine regard-
less of the time elapsed since administration of the last dose;
that dose will be considered protective for up to 3 yr.
Duration of Immunity and Booster Recommendations
Several noninfectious vaccines are routinely administered to dogs
in the US and Canada. Although DOI studies are limited, it is
reasonable to recommend annual boosters with most noninfectious
vaccine indogs considered to be at reasonable risk of exposure to the
infectious agent.
14,24,28,29
RV antigen (glycoprotein G) is highly immunogenic, es-
pecially in the presence of adjuvant. Therefore, the DOI in dogs
vaccinated with two initial doses, 12 mo apart, is expected to
be 3 yr (when using a 3 yr rabies vaccine) in dogs that are $1yr
of age.
Infectious (Attenuated, Avirulent, Modied Live,
Recombinant Viral Vectored) Vaccines
Infectious vaccines must infect the hosts cells to immunize. These
vaccines are the most effective because they can provide the same
types of immunity (cellular, humoral, systemic, and local) that are
produced by natural exposure (i.e., immunity after recovery from
infection or disease). However, the vaccine organisms are atten-
uated and will not cause disease.
14,19,22,26,3033
When the rst modied live canine distemper virus (CDV)
vaccines were made in the 1950s and 1960s, some vaccines were
highly virulent, causing distemper-like disease, including en-
cephalitis, in a high percentage of vaccinated dogs.
20,31,34
Since the
late 1980s, recombinant DNA technology, or genetic engineering,
has been used in the production of veterinary vaccines. The rst
canine vaccine developed and licensed in 1997 using recombinant
DNA technology was the canarypox-vectored recombinant CDV
(rCDV) vaccine. The advantage of this technology is that the
recombinant viral vectored CDV vaccine, unlike the modied live
CDV virus vaccines, cannot revert to a virulent form, because
there is no CDV virus present in the canarypox vaccine. Fur-
thermore, rCDV vaccine cannot replicate in lymphocytes or in the
brain of vaccinated dogs or in wildlife and exotic species that are
susceptible to CDV.
3538
Current canine parvovirus, type 2 (CPV-2) vaccines contain
either CPV-2 or the CPV-2b variant. Vaccines from all the major
manufacturers have been shown to provide sustained (several
years) protection from all the current CPV-2 variants (CPV-2a, b,
and c).
20,3944
The original canine adenovirus, type 1 (CAV-1) vaccines,
which are no longer available in the US or Canada, caused allergic
uveitis and other allergic reactions in a high percentage of dogs;
therefore, CAV-1 vaccines were replaced in the US and Canada by
the safer, but equally or more effective, CAV-2 vaccines. CAV-2
vaccines are used to provide immunity to CAV-1 virus, the
cause of canine infectious hepatitis. Also, they provide protection
Veterinary Practice Guidelines
JAAHA.ORG 11
against CAV-2, a virus that causes and contributes to canine in-
fectious respiratory disease complex.
1,20,22,45
Vaccine Stability
Because antigenic virus/bacteria in infectious vaccines is live, these
products often inherently lack thermostability.
33
To extend the
stability of infectious vaccines during shipment and storage and to
sustain vaccine efcacy, manufacturers typically prepare and sell
infectious vaccines in a lyophilized (freeze-dried) state. Dehy-
drating the product into a cakesignicantly extends the shelf-
life of perishable infectious vaccine antigens. Once diluent is
added to the lyophilized product, the vaccine antigens quickly
regain instability and may lose efcacy over time. Stability after
reconstitution can vary among the various vaccine antigens in
combination (multivalent) products (e.g., modied live virus
[MLV] CDV 1CPV-2 1CAV-2). It is recommended that in-
fectious vaccines, after reconstitution, be administered within
1 hr. Reconstituted vaccine that is not administered within 1 hr
should be discarded.
Once rehydrated, infectious vaccines are highly susceptible to
chemical inactivation. For this reason, it is generally not recom-
mended to cleanse the skin with alcohol before inoculation.
Furthermore, syringes should never be washed and reused.
Chemical residues in the syringe can easily inactivate the infectious
vaccines. Infectious vaccines should be administered before the
expiration date printed on the vial, as infectivity is lost over time.
It is important not to mix noninfectious vaccines with in-
fectious vaccines in the same syringe, unless specied by the
manufacturer, and even then, there may be advantages to ad-
ministering a noninfectious vaccine in a different site on the animal
from the infectious vaccines administration site.
1,14,25
Multiple Dose Vials
Infectious vaccines licensed for use in dogs are not commonly sold
in multiple dose (also called tank) vials. For the same reasons
outlined previously for noninfectious vaccines, use of multiple
dose vials of infectious (parvovirus) vaccine is not generally
recommended.
Routes of Administration
Infectious vaccines contain avirulent live virus or bacteria that
are capable of infecting cells in much the same manner as the
virulent virus or bacteria does during natural infection. Therefore,
infectious vaccines may be administered by the IN route (e.g., Bb 1
canine parainuenza virus [CPiV]) as well as by the paren-
teral route (SQ or IM). Vaccines intended for IN administra-
tion must never be administered parenterally. Furthermore, IN
vaccines administered orally are quickly inactivated and will not
immunize.
Initial Vaccination
One dose of infectious vaccine will prime, immunize, and boost the
immune response, provided the MDA does not interfere with the
vaccine antigen (virus or bacteria). Because it is not practical to
establish the level of maternal antibody in every puppy presented
for initial vaccination, it is recommended that puppies receive doses
of infectious vaccine (e.g., CDV 1CPV-2 1CAV-2) every 34wk
between 8 and 16 wk of age. The nal dose administered at 1416
wk of age should insure the puppy will receive at least one dose of
vaccine at an age when the level of MDA is insufcient to prevent
active (vaccine-induced) immunity. Administration of infectious
vaccine to dogs ,6 wk of age, even in the absence of MDA, is not
recommended.
1,14,24
Because dogs older than 1416 wk of age are not likely to
have interfering levels of MDA, administration of a single initial
dose of an infectious vaccine to an adult dog can be expected to
induce a protective immune response. The administration of
a single, initial dose of infectious vaccine to dogs .16 wk of age is
considered protective and acceptable (Table 1). It is common
practice, however, in the US and Canada, to administer two initial
doses, 2 to 4 weeks apart, to adult dogs without a history of prior
vaccination.
Minimum Age at the Time of Initial Vaccination
In practice, predicting the exact age at which a puppy will rst
respond to administration of an infectious vaccine is difcult. MDA
is the most common reason early vaccination fails to immunize.
Puppies that received colostrum from an immunized dam might not
respond to vaccination until 12 wk of age. In contrast, orphan
puppies and puppies that were denied colostrum might respond to
initial vaccination much earlier. The minimum age recommended
for initial vaccination with an infectious (core) vaccine is 6 wk. Even
in the absence of MDA, administration of an infectious vaccine to
any dog ,6 wk of age may result in a suboptimal immune response
due to age-related immunologic incompetency.
In contrast, administration of an infectious vaccine labeled for
IN administration (e.g., IN Bb 1parainuenza virus) may induce
a protective, local (mucosal) immune response as early as 34wk
of age. MDA does not interfere with local immunity.
Immunization in the Presence of Maternally Derived Antibody
In general, MDA is more effective at interfering with infectious
vaccines than noninfectious vaccines. Various mechanisms have
been suggested, including rapid neutralization of infectious vaccine
12 JAAHA | 47:5 Sep/Oct 2011
virus by maternal antibodies, prevention of replication, and in-
sufcient antigen to prime B cells.
1,14,25
Different vaccine manufacturing methods have been suc-
cessful in developing infectious vaccines that are able to overcome
MDA in puppies at an earlier age. Such methods include increasing
the virus titers within the product (e.g., high titerCPV-2 vac-
cine), using a more infectious virus (which often means more
virulent), or administering the infectious vaccine via the IN route
where the MDA is either limited or not present.
Like the heterotypic measles virus (MV) vaccine, the rCDV
canarypox vectored vaccine has been shown to immunize puppies
24 wk earlier than MLV CDV vaccines.
46,47
However, neither of
these vaccines can immunize puppies that have very high levels of
MDA because of antigen masking. Thus, with all the methods
used to avoid blocking by MDA, it may be possible to immunize
earlier (days or weeks), but not to immunize all puppies at any
age.
19,22,30,37,4549
Onset of Immunity
The onset of immunity after administration of a single dose of
infectious core vaccine is approximately 463 days in the ab-
sence of MDA. Variability among individual dogs and among
different vaccines may alter these times slightly, with CDV
providing the earliest protection within 12 days, CPV-2
providing protection in about 3 days, and CAV-2 providing
protection in 57days.
38,50,51
However, a small percentage of
dogs are genetically incapable of developing an immune re-
sponse to CPV-2 vaccines (estimated 1/1,000 dogs) or to CDV
vaccines (estimated 1/5,000 dogs). These dogs are described as
nonresponders.Immunologic unresponsiveness to vaccination is
determined by genetic factors.
Because the number of nonresponders and low responders
within the canine population is considered low, and nonresponder
status is difcult to conrm, unique breed-specic vaccination
recommendations for dogs are not stipulated in the Guidelines, but
they may be recommended by some breed organizations.
Missed DoseInitial Series
When administering an infectious vaccine for the rst time in the
life of a dog that is $6 wk of age, a single dose, in the absence of
MDA, will immunize. If a puppy exceeds the recommended
interval between doses of the initial vaccination series, it is left
to discretion of the veterinarian whether to administer one or
two additional doses.
If a puppy receives the rst dose in the initial series of core
vaccines between 6 and 8 wk of age but fails to return until 12 or
14 wk of age, administration of two doses, at least 2 wk apart, is
recommended. In contrast, if the same puppy is .14 wk of age
when returning to the veterinarian, administration of a single
dose of an infectious vaccine is expected to immunize.
Missed DoseAdult Booster
The DOI conferred by infectious core vaccines is known to last for
many years. Even if serum antibody levels are determined
to be below protectivelevels, immunologic memory (T- and
B-lymphocytes) is likely to be sustained. Therefore, a single dose
of infectious vaccine administered to an adult dog is considered
protective regardless of the time since a previous vaccine was
administered.
20,31,43,5254
Duration of Immunity and Booster Recommendations
In general, DOI to infectious viral and bacterial vaccines is longer
than to noninfectious viral and bacterial vaccines, and immunity
conferred is generally much longer to viral vaccines than to
bacterial vaccines. DOI is often related to the immunologic
mechanisms of killing or control of the pathogens, and also to the
complexity of the disease and the disease agent.
Infectious core vaccines are not only highly effective, they also
provide the longest DOI, extending from 5 yr up to the life of the
dog. A $3 yr interval is currently recommended for revaccinating
adult dogs with infectious viral core vaccines. In contrast, revac-
cination of dogs with infectious bacterial vaccines (specically IN
Bb vaccine) is recommended annually. The $3 yr recommen-
dation for core vaccines is made on the basis of minimum DOI
studies over the past 30 yr for canine vaccines. These studies were
done by all of the major vaccine companies, as well as by in-
dependent researchers. The results of the studies conducted by
the major manufacturers for canine core vaccine demonstrated
that a minimum DOI for their core vaccines (CDV, CPV-2, CAV)
was $3 yr, based on challenge and/or serologic studies. Similar
minimum DOI studies were conducted for the 3 yr rabies vaccines
using challenge studies only.
14,20,30,5268
Box 1 summarizes key immunologic features of noninfec-
tious and infectious vaccines.
Vaccine Licensure in the United States
Requirements
In the US, the Animal and Plant Health Inspection Service
(APHIS), a multifaceted agency of the USDA, is responsible for
regulating veterinary biologics (vaccines, bacterins, antisera, di-
agnostic kits, and other products of biologic origin) intended for
the diagnosis, prevention, or treatment of animal diseases. For
domestic manufacture, a facility license is required, along with
a license for each product to be distributed. Imported products are
Veterinary Practice Guidelines
JAAHA.ORG 13
BOX 1
Key Immunologic Features of Noninfectious and Infectious Vaccines
Noninfectious Vaccines (inactivated/killed/conventional
and recombinant [r] subunit /avenomous/plasmid DNA)
Infectious Vaccines (MLV/attenuated/recombinant
viral vectored)
Vaccine examples RV
CCoV
CIV
Bb–injectable
Leptospira–2 way/4 way/whole cell and conventional subunit
Lyme–whole cell/recombinant OspA subunit
Crotalus atrox (Western Diamondback rattlesnake avenomous vaccine)
Canine oral melanoma (plasmid DNA vaccine)
CDV, rCDV
CAV-2
CPV-2
CCoV
MV
Bb–IN
CPiV
Initial doses to immunize
(in absence of MDA) ·Generally 2 doses
Interval of time between doses: minimum: 2 wk;
maximum: 6 wk.
Exceptions:
·Rabies–1 dose initially at $12 wk of age, followed
with a second dose within a year after the first dose
·Melanoma vaccine–4 doses
1 dose adequate. Optional–2 doses (not ,2wk
interval between doses)
Parenteral (IM or SQ) route
of administration
Required to be given parenterally Yes
Exception: Never give infectious (IN) Bordetella
parenterally, as it can cause severe disease and death.
Mucosal (IN) route of administration No–should never be given locally on mucosal surface Yes, when recommended
Transdermal route of administration The oral melanoma vaccine is required to be administered transdermally
with a bioinjector.
No
Maternal antibody interference Yes, but less likely, especially in dogs $12 wk of age because of higher
antigenic mass in vaccine and because the agent does not need to
infect and replicate.
Yes. However, MV and rCDV can immunize at an earlier age in
presence of MDA than MLV CDV. Infectious (attenuated,
avirulent, modified live, recombinant viral vectored) vaccines
are more readily inactivated (blocked) by MDA than
noninfectious (inactivated, killed) vaccines, thus it is
necessary to give final dose of puppy series at 14–16 wk
of age.
Replicates in host No (inactivated virus and bacteria are incapable of replication) Yes (must)
Recombinant viral vectored canarypox CDV infects host
cells, but new infectious canarypox virus is not produced
Onset of immunity in absence of MDA Minimum 3–4 wk from the first dose, can be longer 1–2 days for CDV, 3–5 days for CPV-2, CAV-2, (parenteral), as
well as IN Bb, CPiV, and/or CAV-2
Duration of immunity Leptospirosis, Lyme, parenteral Bordetella are probably the shortest
(#1 yr)
Rabies vaccine longest ($3 yr)
Many years to a life time (e.g., parenteralCDV/CPV-2/CAV-2)
1 yr for IN Bb, CPiV, and CAV-2
Revaccination booster Yes. Annually or more often. Exception: Rabies–3 yr booster after
1st dose and dose at 1 yr
$3 yr longer for viral vaccines (CDV, CPV-2, CAV-2)
IN–annual
Humoral (antibody) response Systemic: excellent
Local (mucosal) immunity: little or none
Systemic (IgM, IgG) and local (sIgA): excellent
Cell mediated immunity (CMI) Limited, but some systemic CMI may be stimulated depending on
type of adjuvants used
Excellent–both systemic and local CMI with parenteral and
local (IN) vaccination.
(Box continues)
14 JAAHA | 47:5 Sep/Oct 2011
BOX 1(continued )BOX 1(continued )
Noninfectious Vaccines (inactivated/killed/conventional
and recombinant [r] subunit /avenomous/plasmid DNA)
Infectious Vaccines (MLV/attenuated/recombinant
viral vectored)
Stability Excellent, but limited to expiration date and must be stored properly Lyophilized—excellent, but limited to expiration date
and must be stored properly
Reconstituted—hours depending on the vaccine components
Administration should occur within 1 hr after reconstitution of
all infectious (attenuated, avirulent, modified live, recombinant
viral vectored) vaccines.
Adjuvant Generally required, but not always Rarely, if ever, required
Use in pregnant dogs Not recommended Not recommended
Prophylactic Yes Yes
Therapeutic Only the transdermally administered oral melanoma
vaccine is labeled for therapeutic use.
No
Safety Issues
Reversion to virulence No reversion to virulence Reversion to virulence is of minimal concern with current
infectious (attenuated, avirulent, modified live, recombinant
viral vectored) vaccines when used in dogs $6 wk of age
and not used in pregnant dogs. However, reversion to
virulence is a major concern when the MLV vaccines are
used in certain exotic or wild animal species or used in
puppies ,4 wk of age. These practices are not
recommended. Reversion to virulence is not a concern with
the recombinant vectored CDV vaccine.
Acute adverse reactions (e.g., hypersensitivities) Anaphylaxis, injection site pain, angioedema (facial edema),
injection site granulomas, local inflammation abscesses,
lameness, reactivation of immune-mediated diseases in
predisposed dogs
Fever, lethargy, injection site pain, anaphylaxis, reactivation of
immune-mediated diseases in predisposed dogs
Delayed adverse reactions (e.g., hypersensitivities) Ischemic vasculitis (skin), increase in severity of type
I atopic disease, reactivation of immune-mediated
diseases (e.g., IMHA, IMTP, RA, etc.), and other
hypersensitivity disorders possible in predisposed
dogs (rarely occurs).
Reactivation of immune-mediated diseases (e.g., IMHA, IMTP,
RA, etc.), and other hypersensitivity disorders possible in
predisposed dogs (rarely occurs).
Bb, Bordetella bronchiseptica; CAV-1, canine adenovirus, type 1 (cause of canine viral hepatitis)—protection from CAV-1 infection is provided by parenterally administered CAV-2 vaccine; CAV-2, canine adenovirus, type 2;
CCoV, canine coronavirus cause of enteric coronavirus infection (antigenically distinct from the canine respiratory coronavirus [CRCoV]); CDV, canine distemper virus; CIV, canine influenza virus—H3N8; CPiV, canine
parainfluenza virus; CPV-2, canine parvovirus, type 2; DOI, duration of immunity; IgG, immunoglobulin G—a class of humoral antibody; most common type associated with immune response to parenteral vaccine; also the
most common class of antibody measured as serum titers; IgM immunoglobulin M—a class of antibody, generally short lived and associated with early infection and initial vaccination; IM, intramuscular (route of
administration); IMHA, immune-mediated hemolytic anemia; IMTP, immune-mediated thrombocytopenia; IN, intranasl; MLV, modified live virus—attenuated virus vaccine; MV, measles virus; OspA, outer surface protein A
(antigen) of Borrelia burgdorferi; RA, rheumatoid arthritis, RV, rabies virus; sIgA, secretory immunoglobulin A—a class of antibody, most commonly associated with a local (mucosal) immune response after IN vaccination;
SQ, subcutaneous.
Veterinary Practice Guidelines
JAAHA.ORG 15
issued a permit for sale and distribution. This work is done by
APHISs Center for Veterinary Biologics (CVBs).
Before the issuance of a license or permit, the manufacturer of
a vaccine intended for sale and distribution within the US must
demonstrate, to the satisfaction of the USDA CVB, that the pro-
posed product is pure, safe, potent, and efcacious. The facility in
which the product is prepared must meet USDA standards and pass
inspection by the CVB. After licensure, each batch of vaccine is
subject to random premarketing testing by the CVB to verify the
manufacturers quality assurance and quality control.
Purity assures the nal product is free of extraneous micro-
organisms and extraneous material (organic or inorganic).
Safety is dened as freedom from properties causing undue
local or systemic reactions when the vaccine is used as labeled. As
part of the prelicense process, attenuated (live, whole agent)
vaccines are evaluated in dogs to assess the potential of the vaccine
organism to revert to virulence and the potential for dogs to shed
the vaccine virus and/or bacteria. In addition, eld safety studies
are performed in a large group of dogs (typically at least 600),
a substantial proportion of which must be at the minimum age
indicated for administration. Postmarketing surveillance, in-
cluding investigation of consumer complaints, is intended to
identify relatively rare or uncommon safety issues that might not
be detected in a prelicense eld safety study. It should be noted
safety studies are not a guarantee that a vaccine, once released for
sale, will be entirely free of risk.
Efcacy is the ability or capacity of the product to effect the
result for which it is offered when the product is used according to
its label. Vaccine efcacy is conventionally determined through
dened vaccination-challenge studies conducted by the manu-
facturer. Although challenge methods and criteria for evaluating
protection will vary with the immunizing agent, tests are generally
conducted under controlled conditions using seronegative dogs of
the youngest age recommended on the label.
Potency is the relative strength of a biologic product as de-
termined by test methods approved by the CVB. Potency testing is
intended to assure that each serial (batch) of vaccine marketed is equal
to, or more potent than, a dened reference serial of known efcacy.
DOI is noted here due to its interest to practitioners. However,
the denition of the term is often interpreted differently in dif-
ferent contexts. The CVB views DOI as conrming, typically by
a vaccination-challenge study, that the immunity conferred by the
product lasts at least as long as indicated on the label. Practitioners
may view these studies as conrming efcacy at a specied point,
rather than a demonstration of the maximum reasonable duration
of immunologic protection conferred to patients. Traditionally,
vaccine challenge models were intended to demonstrate the onset
of immunity in younger dogs using products titrated to the
minimum protective dose. These products typically carried the
historically based label recommendation for annual revaccination.
Therefore, for most of the canine vaccines licensed in veterinary
medicine, the CVB has not required manufacturers to conduct
DOI studies, unless making a specic claim differing from 1 yr.
Current CVB policy requires manufacturers to conduct DOI
studies for all rabies vaccines and all new (novel) antigens, re-
gardless of the revaccination interval.
Conditional Licensure
The time to market for a new vaccine can require several years. The
USDA utilizes a pathway called conditional licensure to speed the
availability to veterinarians of vaccines that address unmet needs,
emergencies, or other special circumstances. In this process,
a manufacturer is required to demonstrate that the product is
safe, pure, has a reasonable expectation of efcacy, and that it is
manufactured in compliance with standard USDA regulations.
The USDA typically places time limits on such a license, during
which the manufacturer must provide data to fully demonstrate
efcacy or appropriate progress toward so doing. The USDA
requires distinctive labeling to differentiate those products
marketed under a conditional license, and the label must state
that the product is conditionally licensed. The DOI of a condi-
tionally licensed vaccine has not been conrmed by a vaccination-
challenge study at the time the product is released for sale in
the US.
(Conditional canine vaccines at this writing are: Crotalus
atrox toxoid [Western Diamondback rattlesnake vaccine].)
Vaccine Licensure in Canada
The CFIA, under the legislative authority of the Health of Animals
Act and Regulations, is responsible for regulating veterinary bio-
logics in Canada. This regulatory program forms an integral part of
Canadas National Animal Health Program, which strives to
protect the health of food producing animals, domestic pets,
wildlife, and the Canadian public, as well as to safeguard the
environment by preventing the introduction and spread of in-
fectious animal diseases.
Responsibilities of the CFIA in licensing vaccines for use in
veterinary medicine include:
·Licensing of veterinary biologics, including verication of mas-
ter seeds and prelicensure product evaluation
·Licensing of veterinary biologics manufacturing facilities
·Issuance of import and/or export permits to Canadian importers
and/or exporters of veterinary biologics
·Postlicensure monitoring, including:
16 JAAHA | 47:5 Sep/Oct 2011
serial release monitoring of veterinary biologics for purity,
potency, and safety
investigations of consumer complaints
inspections of manufacturers and Canadian importers of vet-
erinary biologics
·Scientic research in support of regulations
·Technology development, including collaborative research with
industry partners.
The standards for licensure of any veterinary vaccine in
Canada are similar to those required in the US. Regulated products
include vaccines, immunoglobulin products, and diagnostic kits
that are used for the prevention, treatment, or diagnosis of diseases
in animals, including domestic livestock, poultry, pets, wildlife, and
sh. To meet the requirements for licensure, veterinary biologics
must be shown to be pure, potent, safe, and effective when used in
the target species according to the manufacturers label recom-
mendations. In addition, the licensing submission must also
contain supporting data demonstrating that the product can be
manufactured and used without adversely affecting animal health,
human health, food safety, or the environment.
Serologic Testing to Determine and
Monitor Immunity
Interpreting Results of Serologic Tests
Despite the confusion and controversy surrounding antibody
testing, these serologic tests are useful for monitoring immunity to
CDV, CPV-2, CAV-1, and RV. Because of this, many practitioners
perform large numbers of tests for antibodies on a routine basis at
state diagnostic and commercial laboratories or the tests are done
with in-house diagnostics. The tests are also medically useful to
ensure that a dog responds to a specic core virus vaccine and/or to
determine if immunity is present in a previously vaccinated dog.
Those tests are also used to demonstrate protective immunity as
well as DOI.
5669
Antibody assays for CDV and CPV-2the two tests performed
most oftenare the tests of greatest benet in monitoring im-
munity, especially after the puppy vaccination series. The serologic
test considered the gold standardfor CDV is virus neutraliza-
tion (VN). VN and hemagglutination inhibition (HI) are the gold
standard tests for antibodies to CPV-2.
1,14,67
Although most state
diagnostic laboratories use the gold standard tests, most commer-
cial laboratories use other methods, such as immunouorescence
assays or enzyme immunoassays. During the past 5 yr, most, if not
all, laboratories have qualied and standardized their methodolo-
gies with samples that were tested by the gold standard methods.
Also, standardization of these tests was done with samples collected
from dogs protected from challenge with virulent virus.
54
Notwithstanding this development, titer results may vary
among tests and between laboratories. Most state diagnostic
laboratories report classic titers, in which two-fold dilutions of
serum are made and the highest dilution that neutralizes the virus
(CDV, CPV-2, CAV-1, RV), inhibits hemagglutination by the virus
(CPV-2), or binds to viral antigen and is detected with a uorescent
or enzyme probe (CDV, CPV-2, RV) is reported. Using the
standard two-fold dilution technique, the amount of error is
approximately a four-fold dilution. The titer of a single serum
sample would be in the range of one doubling dilution below the
reported value and one doubling dilution above the reported value.
For example, a CDV virus neutralization titer reported at 128 in
reality is between 64 and 256; similarly, a CPV-2 HI titer of 1,280
is between 640 and 2,560. Some laboratories simply report results
of .5 as positive and ,5 as negative, and other tests are simply
positive (antibody is present) or negative (no antibody was
detected).
There are currently two in-hospital tests that provide a pos-
itive or negative result that have been approved by the USDA. A
positive CDV result on these tests indicates that a serum sample has
an antibody titer that is .8 on the VN test. A positive result for
CPV-2 indicates the serum sample has an antibody titer that is
.20 with the HI test. A negative test indicates that the dog has
a titer less than these values or that it has no antibody. Obviously,
some dogs with a negative result on this test are immune, but
most of these dogs would benet from revaccination by de-
veloping a higher titer. After performing and comparing many
serologic tests for thousands of dogs, researchers found that ap-
proximately 1565% of dogs will have low (#32 VN) or no anti-
body to CDV. A similar percentage but different dogs will have
low or no antibody to CPV-2 (#80 HI) on the test. With CDV
and/or CPV-2 tests, dogs with a negative result, regardless of the
test used, should be considered as having no antibody and may
be susceptible to infection with CDV and/or CPV-2; thus, these
dogs should be revaccinated to ensure there is immunity. In
contrast, any dog with a positive result, regardless of the test
performed, should be considered immune and does not need to
be revaccinated.
42,54
Applications of Serologic Testing
On completion of the puppy core vaccination series with the last
dose given at 1416 wk of age, a dog can be expected to have an
antibody titer or positive test result, regardless of the serologic test
performed, provided the serum sample is collected $2 wk after
the last dose of vaccine. If the dog does not have antibody, it
should be revaccinated, perhaps using a different product, and
then retested $2 wk later. If the antibody test is again negative,
Veterinary Practice Guidelines
JAAHA.ORG 17
the individual dog should be considered a low responder or
a nonresponder (see Part I, Types of Vaccines) and possibly in-
capable of developing a protective antibody response.
Challenge with virulent virus or serologic testing is the only
practical way to ensure a puppy develops an immune response after
vaccination. The serologic test is the only acceptable way to ensure
a client-owned dog develops an immune response. Young dogs are
at greatest risk of infection from CDV and CPV-2, and these
infections lead to severe disease and death in $50% of susceptible
puppies. Antibody tests are useful as a medical procedure to en-
sure the dog develops an immune response to CDV and CPV-2
vaccines after the primary series of vaccinations. Vaccines can
fail for various reasons.
25
However,thefollowingarethethree
main reasons for vaccination failure: (1) the puppy has a suf-
cient amount of MDA to block the vaccine; (2) the vaccine is
not immunogenic (e.g., if the vaccine was improperly stored);
or (3) the dog is a poor or nonresponder (i.e., the immune
system fails to recognize the antigenic determinants of the
specicvaccine).
The most common reason for vaccination failure in young
dogs is that MDA blocked the vaccine response. During the initial
puppy vaccination series, the last dose of CDV and CPV should be
administered at 1416 wk of age. At this age, MDA should be at
a level that will not block active immunization in most puppies
(.98%) when a combination MLV vaccine is administered.
1,24,25
When the puppy fails to produce antibody $2 wks after a dose of
vaccine administered at 1416 wk, the practitioner must consider
the other two explanations for vaccine failure. If, after one or
more attempts at revaccination with a product different than the
one originally used, the dog fails to develop an antibody response
to CDV or CPV-2 by VN or HI test, the dog should be considered
a transient or permanent nonresponder.
Because immunologic nonresponsiveness is genetically con-
trolled, certain breeds or families of dogs may be suspected to have
a higher prevalence of low or nonresponders than the general
canine population. It is believed by some (but not proven) that the
increased susceptibility to CPV-2 recognized in certain rottweilers
and Doberman pinschers during the early and mid-1980s (re-
gardless of their vaccination history) was due to an increased
prevalence of nonresponders; it was also demonstrated that some
early vaccination failures were attributable to the poor quality
vaccines available at that time. Today, these two breeds appear to
have no greater numbers of low or nonresponders than other
breeds.
52,68
A high titer of antibody to CDV and/or CPV-2 as a result of
active immunization from vaccination or from natural exposure
protects from infection; therefore, no detectable virus replication
occurs. Although a virus may be capable of replicating in a dog
whose antibody titers have decreased, memory B and T cells should
provide an anamnestic (secondary) humoral- and cell-mediated
immune response that limits virus replication and prevents dis-
ease. Immune responses to modied live vaccines like CDV, CPV-2,
and CAV-2, because of their complexity, always stimulate both
humoral- and cell-mediated immunity. Although antibody is a
product of humoral immunity, cellular immunity is always re-
quired for antibody production, as T-helper cells must be activated
by the virus to produce a B-cell response. Therefore, although
rarely considered, the presence of antibody in the dog to specic
viruses demonstrates not only humoral immunity but also that
cell-mediated immunity was stimulated as well. It is also incorrectly
assumed that antibody to MLV vaccines containing CDV, CPV-2,
and CAV-2 often disappears after relatively short periods of
time (e.g., months or a few years). It was shown in many studies
that antibody to those viruses persisted for many years, even in
the absence of the viruses or revaccination.
The persistence of antibody to these viruses is from a pop-
ulation of long lived plasma cells that has been referred to as
memory effector B cells.This is a population of cells that
continues to produce the antibody they were programmed to
produce (e.g., CDV) long after vaccination. Too much emphasis
has been placed on the antibody titer (dilution of antibody that is
positive). It was found repeatedly in controlled challenge studies
with CDV, CPV-2, and CAV-1 that actively immune dogs (vac-
cinated at 1416 wk of age or younger dogs without MDA) with
actively produced antibody, regardless of titer or test used to detect
the antibody, were resistant to challenge. Therefore, it is not nec-
essary, as some have suggested, to have an antibody titer of $32
with the serum neutralization test for CDV or a titer of $80 on
the HI test for CPV-2 for the vaccinated dog to be completely
protected when challenged. Thus, most of the concerns ex-
pressed about the variability in titers among serologic tests have
little or no validity when applied to protection from CDV, CPV-
2, CAV-1, and RV. Furthermore, with the development of some
of the in-hospital tests, serum dilutions are not performed and
titers are not the end point; instead, the test is considered pos-
itive or negative.
43,54
Application of Serology to Evaluate Duration of Immunity
Antibody tests can also be used to demonstrate the DOI to vaccines
or from natural immunization. As discussed previously, dogs were
shown to maintain antibody titers to the core viruses CDV, CPV-2,
and CAV-1 in viral-free environments for many years. In a study
reported in 1997, dogs vaccinated with a product containing CDV
and then placed in an environment without CDV maintained
18 JAAHA | 47:5 Sep/Oct 2011
antibody titers for at least 10 yr.
61
In a more recent controlled
study of puppies without MDA vaccinated at 7 and 10 wk of age
(and housed with nonvaccinated dogs to ensure CDV, CPV-2, and
CAV-1 were not present), it was shown that vaccinated dogs
maintained antibody titers for .4yr.
61,54,69
These and other
studies clearly demonstrated that antibody correlated with pro-
tection from infection and/or protection from disease because the
vaccinated antibody-positive dogs remained healthy after experi-
mental challenge with virulent strains of the viruses. These and
other studies also clearly demonstrated that antibodies to the core
vaccine viruses might persist in the absence of revaccination for
many years. All of the major vaccine manufacturers have products
that were shown to provide a minimum DOI of 3 yr. In addition,
it was demonstrated that antibody correlated with protection
from infection and/or protection from disease because the vac-
cinated antibody-positive dogs remained healthy after experi-
mental challenge with virulent strains of the viruses.
5557,69
In
contrast, vaccinated dogs that did not develop antibody to CDV,
as well as unvaccinated control dogs that were antibody negative,
became infected. Many dogs develop disease and die when chal-
lenged. When antibody is absent (irrespective of the serologic test
used to determine this fact), it should be assumed the dog is
susceptible to infection and may develop disease. Therefore, an-
tibody negative dogs should be revaccinated. Similarly, dogs that
have been actively immunized by vaccination or naturally by in-
fection that have antibodies to CDV, CPV-2, or CAV-1 do not
need to be revaccinated. Some clients are now having titers per-
formed for CDV and CPV-2 in lieu of revaccinating.
Antibody titers to additional vaccine antigens are sometimes
determined to diagnose susceptibility to disease, but the best
correlations between antibody and protective immunity are as
stated previously for CDV, CPV-2, CAV-1, and RV. Very sensitive
and well-documented titers to RV are done by a small number of
approved laboratories. Although most widely used when shipping
dogs to rabies-free countries, rabies titers are sometimes performed
in dogs that developed an adverse reaction to the vaccine.
7072
However, RV titers cannot currently be used in place of revac-
cination, which is required on an annual or triennial basis
depending upon governing law. Medical exemption laws exist in
certain areas where a dog with a known medical condition can be
exempted from rabies vaccine. However, a titer cannot be used in
place of vaccination. When RV vaccination is not current, the dog
must be considered unvaccinated, and if it bites someone, it must
be quarantined.
Antibody titers to vaccines other than CDV, CPV-2, CAV-1,
and RV have limited or no value because the antibody may per-
sist for a short time (e.g., Leptospira products), or there is no
known correlation between serum antibody test routinely per-
formed and protection (e.g., CPiV, Lyme, Leptospira). However,
researchers are attempting to nd serologic correlates of pro-
tective immunity for diseases other than the four core viruses
(CDV, CPV-2, CAV, and RV).
Vaccine Adverse Events
Since the original canine vaccines were developed and licensed
.50 yr ago, there has been a continuing effort to make canine
vaccines safer and more efcacious. Today, it is generally agreed
that canine vaccines have an excellent safety record. Although AE
documentation in veterinary medicine is limited, severe adverse
reactions are considered uncommon. Vaccines are, however, bio-
logic products and can cause unpredictable adverse effects in
some dogs after administration. The following section is intended
to characterize types of vaccine AEs possible in dogs, provide
information on how to report known and/or suspected AEs, and
offer suggestions for mitigating the risk of vaccination in patients
with a history of AEs.
Vaccines are biologic products and, as such, provoke a series of
complex immune reactions that may culminate in rapid-onset side
effects lasting from a few hours to a few days. Rarely do these self-
limiting side effects escalate into serious AEs (SAEs). For this
reason, veterinarians are encouraged to inform clientele that their
pet, regardless of breed or size, may manifest transient side effects
for up to 2, and possibly 3, days after administration of any vaccine
or any combination of vaccines. Side effects commonly observed
include: reduced or loss of appetite (lasting for one or two feed-
ings), pain at the injection site, lethargy (lack of activity), re-
luctance to walk and/or run, and mild fever. Treatment is usually
not indicated; however, some veterinarians have reported ad-
ministering short-term symptomatic treatment (e.g., a non-
steroidal anti-inammatory drug [NSAIDs]). It is recommended
that clientele be advised to contact the practice in the event any
physical and/or behavioral manifestations progressively worsen or
continue beyond 23 days. Clientele should be advised to contact
the practice at any time if signs of systemic illness, such as
vomiting, diarrhea, seizures, facial swelling, collapse, or difculty
breathing, develop.
Vaccine AEs are underreported in veterinary medicine. How-
ever, mechanisms are in place for reporting such reactions; veter-
inarians are strongly encouraged to participate by reporting all
known or suspected AEs associated with vaccine administration.
In the US and Canada, vaccine AEs should be reported to the
Technical Services section of the manufacturer of the vaccine(s)
believed to be associated with the AE. If multiple vaccines from
different manufacturers were administered to an individual patient
Veterinary Practice Guidelines
JAAHA.ORG 19
at the same appointment, reports should be submitted to each
manufacturer. Furthermore, it is recommended that reports in-
clude reference to any concurrently administered drug and/or
therapy. Reports can be made directly to the manufacture via
(toll-free) telephone call.
In the US, vaccine AEs may also be reported on-line to the
CVB (reporting information is outlined in the following).
In Canada, vaccine AEs may also be reported to the CFIA
(reporting information is outlined in the following).
What Constitutes a Vaccine Adverse Event?
A vaccine AE is generally dened as any undesirable side effect or
unintended effect (including lack of desired result) associated with
the administration of a licensed biologic product (vaccine). For
vaccines administered to dogs, AEs are those involving the health of
the treated dog and include the apparent failure to protect against
a disease. An AE event includes any injury, toxicity, or sensitivity
reaction associated with the use of a vaccine, whether the event can
be directly attributed to the vaccine. In other words, it is appro-
priate to report any known or suspected negative event associated
with vaccination.
Although the incidence of vaccine AEs is unknown and
causality cannot always be conrmed, the list that follows includes
categories of adverse reactions that have been attributed to vaccine
administration. The list of categories is not considered compre-
hensive; other, undocumented adverse reactions associated with
vaccine administration could occur. Furthermore, causality has not
been denitively established for each of the categories listed:
·Injection-site reactions: lumps (abscess, granuloma, seroma),
pain, swelling, hair loss associated with ischemic vasculitis
·Transient postvaccinal nonspecic illness: lethargy, anorexia,
fever, regional lymphadenomegaly, soreness, abortion, enceph-
alitis, polyneuritis, arthritis, seizures, behavioral changes, hair
loss or color change at the injection site, respiratory disease
·Allergic (hypersensitivity) and immune-mediated reactions:
Type 1 (acute anaphylaxis): angioedema (especially the head),
anaphylaxis (shock), and death
Type 2 (cytolytic): immune-mediated hemolytic anemia,
immune-mediated thrombocytopenia (suspected only; causal-
ity has not been conrmed)
Type 3 (immune-complex): cutaneous ischemic vasculopathy
associated with rabies vaccine, corneal edema (blue-eye)asso-
ciated with CAV-1 vaccine, immune-mediated disease
·Failure to immunize: maternal antibody interference with vac-
cination is considered the most common cause; administration
of vaccine at a volume and/or dose less than that prescribed
by the manufacturer; nonresponder(genetic predisposition?);
inactivation of vaccine antigen (e.g., allowing reconstituted in-
fectious [attenuated, avirulent, modied live, recombinant viral
vectored] vaccine to stand at room temperature for .2 hr),
mixing of incompatible vaccines in the same syringe
·Tumorigenesis: vaccine-associated sarcoma or other tumors
·Multisystemic infectious/inammatory disorder of young
Weimaraner dogs: may be genetically linked to both a poorly
characterized immunodeciency and to autoimmune disorders
(e.g., hypothyroidism and hypertrophic osteodystrophy [HOD]
that are detected shortly after vaccination
·Vaccine-induced immunosuppression: associated with rst or
second dose of combination MLV vaccines containing CDVand
CAV-1 or CAV-2 with or without other vaccines (e.g., CPV-2,
CPI). Immunosuppression begins 3 days after vaccination and
persists for 710 days. The suppression may be associated with
increased susceptibility to other diseases.
17
·Reactions caused by the incorrect or inappropriate adminis-
tration of vaccine: fatalities have been reported after subcuta-
neous administration of an avirulent-live Bb bacterin (intended
for IN administration); inadvertent or intentional administra-
tion of vaccine by the intravenous route
·Reactions associated with residual virulence attenuated vac-
cine: postvaccinal sneezing associated with IN administration of
attenuated vaccine (e.g., Bb 1parainuenza virus)
·Vaccine-induced interference with diagnostic tests: false-
positive polymerase chaine reaction (PCR) test results for parvo-
virus antigen in feces in dogs recently receiving a MLV parvovirus
vaccine. Not an adverse reaction.
·Reversion of vaccine virus to a virulent pathogen: generally
considered rare to nonexistent among currently licensed canine
vaccines when vaccines are used in the species for which they
were licensed. This can become a signicant problem when
vaccine is used in the wild and/or exotic animals.
8,9,12,13,1618
How to Report a Known or Suspected Vaccine Adverse Event
Veterinarians are encouraged to participate in the vaccine AE
reporting process by reporting suspected and known AEs to one of
the following:
·Vaccine Manufacturer: Companies that manufacture vaccines
maintain a technical services section that will accept and ad-
dress AE reports from veterinarians who use their product(s).
Veterinarians are encouraged to report AEs to the manufacturer(s)
before contacting the appropriate regulatory agency. Manufac-
turers are required to maintain les of any reported vaccine AE.
However, manufacturers are under no obligation to compen-
sate the owner or the veterinarian for diagnostic or treatment
services related to a known or suspected AE.
20 JAAHA | 47:5 Sep/Oct 2011
·CVB: Subsequent to reporting a known or suspected vaccine
AE to the manufacturer, veterinarians practicing within the US
may contact the USDA, APHIS CVB in one of the following
ways:
Once an adverse event has been reported to the manufacturer,
the CVB may be contacted:
·Online: https://web01.aphis.usda.gov/CVB/adverseeventreport.
nsf/Adverse%20Event%20Report%20Form?OpenForm
·By fax or mail: download the PDF form at http://www.
aphis.usda.gov/animal_health/vet_biologics/publications/
adverseeventreportform.pdf and FAX to (515) 3376120 or by
mail to the CVB.
·By telephone: AEs may also be reported by calling the CVB at
(800) 7526255.
Canadian Food Inspection Agency
In Canada, CFIA is responsible for licensing veterinary biologics,
including veterinary vaccines, manufactured and/or used in
Canada. The licensing program operates under the Health of
Animals Act and Regulations, and is administered by the Canadian
Centre for Veterinary Biologics.
The Canadian Health of Animals Regulations require all
holders of product licenses and import permits to report all
serious expectedor serious unexpectedsuspected AEs, in-
cluding lack of efcacy, to the Canadian Centre for Veterinary
Biologics of the CFIA within 15 days of receiving notice of the
event from a veterinarian or animal owner. This can be done by
notifying Canadian Centre for Veterinary Biologics directly or
through the licensed vaccine manufacturer or importer.
In Canada, Form CFIA/ACIA 2205 Notication of Sus-
pected Adverse Events to Veterinary Biologicscanbeusedto
report suspected AEs: http://inspection.gc.ca/english/for/pdf/
c2205e.pdf
The Canadian Veterinary Biologics Guideline 3.15E: Guide-
line for Reporting Suspected Adverse Events Related to Veterinary
Biologics(available: http://www.inspection.gc.ca/english/anima/
vetbio/info/vb315e.shtml) provides guidelines for dening a sus-
pected AE related to veterinary biologics as one of the following:
AE, SAE, unexpected AE, and lack of efcacy. The denitions
for AE, SAE, and unexpected AE are found in Section V of this
guideline and are consistent with the International Cooperation
on Harmonization of Technical Requirements for Registration of
Veterinary Medicinal Products (VICH)s Guideline 24: Pharmaco-
vigilance of veterinary medicinal products: management of adverse
event reports (AERs). A causality assessment should also be assigned
to each SAE. Each case should be classied as probable, possible,
unlikely, or unknown.
Managing Adverse Event Risk in Individual Patients
Specic recommendations for mitigating the risk of a vaccine AE in
dogs have not been validated. Efforts to manage risk are highly
varied and largely unsubstantiated. It is not possible to completely
avoid a vaccine AE in any patient. Vaccine risk management should
focus on dogs having a known or suspected history of a vaccine
reaction and in small breeds. Recommendations are outlined in the
following.
The reduction of vaccine volume to mitigate risk of an AE is
not recommended. Doing so may result in suboptimal immuni-
zation or no immune response without reducing risk of an AE.
Vaccine dose is not based on size (body mass); therefore, small dogs
require the same dose of vaccines as large dogs.
Patients with a Known or Suspected Vaccine Adverse
Event History
Acute hypersensitivity (nonsystemic) and injection-site reactions
are among the most common vaccine AEs reported because they
occur within hours or a few days after vaccination. The decision to
administer vaccine to any patient with a history of having expe-
rienced an acute-onset (minutes to 12 days postvaccination)
reaction is left to the discretion of the veterinarian. History of an
acute-onset AE is not predictive of future risk.
Administration of an antihistamine or NSAID before vacci-
nation to prevent transient postvaccinal nonspecic illness has not
been studied adequately in dogs to make specic recommendations
on their use or benet. However, it is common practice to ad-
minister an antihistamine (diphenhydramine, 24 mg/kg orally or
1 mg/kg parenterally) to patients with a history of an acute ad-
verse reaction. A single dose is generally administered 1530 min
before administering vaccine. In such cases, it is recommended
that the patient remain at the practice and be monitored for at
least 30 min postvaccination.
In an attempt to mitigate the risk associated with adminis-
tering vaccine to any patient with acute-onset vaccine AE, veter-
inarians may also elect to administer the same vaccine type but one
produced by a different manufacturer.
The decision to administer pretreatment and/or a vaccine
produced by a different manufacturer to any patient with a history
of having a known or suspected vaccine AE does not guarantee that
an AE will be prevented.
It is reasonable to avoid administration of any vaccine to
patients with a history of systemic disease suspected to be asso-
ciated with previous vaccination (e.g., immune-mediated hemo-
lytic anemia, immune-mediated thrombocytopenia) or known to
be caused by vaccine (vaccination-site cutaneous ischemic vas-
culitis after administration of rabies vaccine). In lieu of annual or
Veterinary Practice Guidelines
JAAHA.ORG 21
triennial revaccination, assessment of antibody titers can be de-
termined (CDV and CPV) (see Serologic Testing). Dogs with
apositivetiter are considered protected. These patients can be
considered to have sufcient immune memory to mount a pro-
tective humoral immune response for several years and may not
require vaccination. Dogs with a negativeantibody titer may be
susceptible to infection. Whether to administer vaccine to dogs
with a negative antibody titer is left to the discretion of the vet-
erinarian. However, a negative antibody test for CDV and/or CPV-
2 may indicate the dog is susceptible to either of these signicant
diseases.
The decision not to administer rabies vaccine for health
reasons is problematic in locations that require rabies vaccinations
yet do not grant rabies exemption authority to veterinarians. Some
states and/or provinces do grant rabies vaccination exemption
authority to veterinarians who have examined a patient and de-
termined, for health reasons, vaccine should not be administered.
Such waivers generally remain in effect until the patient is deemed
sufciently healthy to receive the vaccine. Veterinarians are urged
to contact state, provincial, and/or local authorities to determine
whether such exemption authority exists.
Small Breed Dogs
One study addressed vaccine AEs in .1.2 million dogs that re-
ceived .3.4 million doses of vaccine.
73
This study provided im-
portant insight on risk associated with administration of multiple
vaccine doses to small breed dogs at the same appointment.
History of a vaccine AE in a small breed dog is not predictive of
future risk. Any dog, regardless of size, breed, gender, or age, can
experience a vaccine AE.
Mitigating risk in small dogs (puppies and small breeds) by
reducing the volume of vaccine is not recommended. Doing so may
result in a suboptimal response to the vaccine and may not
eliminate risk associated with hypersensitivity to one or more
vaccine constituents. As with all dogs, small breed dogs should be
assessed for risk of exposure to infectious pathogens and only those
vaccines considered essential should be administered. Further-
more, prioritizing administration of core vaccines (CDV, CPV-2,
CAV-2, and rabies) to all dogs at the appropriate age (see Table 1)
is recommended.
The decision to administer one or more noncore vaccines to
a dog should be based on reasonable knowledge of exposure risk in
the individual patient. It should also be noted that most of the
noncore vaccines listed within the Guidelines are inactivated
(killed) vaccines and that these vaccines may be associated with
a higher incidence of AEs when administered at the same time
as other vaccines, particularly in small breed dogs. Therefore,
veterinarians may wish to delay administration of inactivated
noncore vaccines to small breed dogs until after completion of the
initial core vaccine series.
Legal Considerations
·Veterinarians have considerable ability to use biologics in a dis-
cretionary manner.
·Continuous medical decision making is an inherent aspect of
veterinary medicine. There is no reason to believe that decisions
regarding vaccine selection and use will carry any greater legal
risk than the myriad of other medical decisions made in daily
practice. Relative risk for utilizing these guidelines in developing
patient vaccination protocols is considered low.
·The best method for insulating a practitioner from legal liability
relative to vaccination or anything else is effective client com-
munication. Client communication of risk and/or benet in-
formation should be in direct and simple terms.
·With respect to documentation, practitioners must determine
the method that best suits their practice and level of risk tolerance.
Do Veterinarians Have Professional Discretion
in the Use of Vaccines in Their Practice?
Yes, with a few limitations. The recommendations contained in the
Guidelines may differ in places from statements on product labels.
However, veterinarians in small animal practice in the US have
considerable discretion in exercising their judgment relative to the
use of veterinary biologic products licensed by the USDA within
their professional practice.
a
The same is true for veterinarians in
Canada using biologic products approved under the Canadian
Food and Drug Act.
b
As such, practitioners have the ability to
incorporate use of the Guidelines into their practices.
The USDA CVB regulates the licensure and preparation of
most veterinary biologics, including all material on their labeling.
CVB does not regulate the practice of veterinary medicine. Al-
though CVB does have the statutory authority to stop the sale,
barter, or exchange of any worthless, contaminated, dangerous,
or harmful virus, serum, toxin, or analogous product,they would
only take action against a small animal practitioner under ex-
traordinary circumstances. Before initiating such action, CVB
would most likely contact the veterinarian and/or undertake a
profession-wide educational initiative.
c
Vaccines licensed by the USDA and prepared in establish-
ments licensed by the USDA are not directly subject to the Animal
Medicinal Drug Use Clarication Act (AMDUCA) or Food and
Drug Administrations (FDA) implementing regulations. How-
ever, it is possible for the FDAs Center for Veterinary Medicine to
regulate some products that most practitioners would consider
22 JAAHA | 47:5 Sep/Oct 2011
biologicals. Products that are approved by the FDA are subject to
AMDUCAsandFDAs established specic rules for extra-label
drug use. Products regulated by the USDA may be identied by the
USDA Establishment Numberthat appears on labeling.
States may also regulate the discretionary use of biologic
products by veterinarians. This can be confusing, as the state and
federal terminology may be similar but applied differently. The
statesdenition of drugmay include biologic products, and the
state may use the term extra-labeldifferently than the federal
application.
d
Veterinarians should be aware of any state-specic
restrictions in their states veterinary practice act or implementing
regulations. However, it is the authorsbelief that such restrictions
are sufciently general that they should not interfere with the
ability to use these Guidelines. In Canada, the provinces have the
legal authority to regulate the veterinary profession but no au-
thority whatever relating to trade in drugs, medications, and
biologics. In this context, the provincial veterinary legislation may,
for instance, require that a veterinarian obtain the informed
consent of the client before using a substance in a manner that
differs from its labeled indications.
Rabies vaccine represents a unique class of products due to the
public health concern. The USDA places restrictions on the licenses
for rabies products, such that their distribution in each state is
limited to authorized recipients as designated by proper state
ofcials (e.g., the state veterinarian) and under such additional
conditions as these authorities may require. Each state, in turn, has
its own rabies control program. The substance of this law varies
among jurisdictions and can encompass state, provincial, and/or
local requirements. A common theme to this regulation is com-
pulsory vaccination, irrespective of the label statements that the
products are for use in healthy animals. Sometimes veterinarians
and/or clients desire to forego rabies vaccination, believing it to be
contraindicated due to the health or age of the dog. Veterinarians
must be very careful in such circumstances. Although some states
have procedures for addressing this situation, it is not addressed in
most states.
e
Veterinarians must not assume they have the discre-
tion to recommend against vaccination in the face of mandatory
state vaccination laws. Therefore, it is imperative that veterinarians
investigate, understand, and follow the legal requirements for rabies
vaccination in the areas in which they practice. The same approach
is prudent in Canada.
Potential for Liability Associated with Vaccine Administration
Potential liability for medical decision making is a fact of life for
any health care provider, including veterinarians. This potential
professional liability encompasses all aspects of veterinary practice,
including the selection and use of vaccines and other biologic products.
Most lawsuits against practitioners are grounded in negligence, al-
though the range of possible legal liability theories is broad and limited
only by the creativity of the plaintiff s attorney. There is no reason to
believe a veterinarians use of vaccines would be treated differently or
carry any greater risk than other areas of small animal practice.
Medical Negligence
Legal actions against a veterinarian alleging professional negligence
are commonly called malpracticeor medical malpracticecases.
The body of law for professional medical negligence has evolved in
the context of human medicine. Most jurisdictions apply many
of the legal concepts developed in the litigation of physician
malpractice cases to veterinary malpractice cases, particularly the
requirement for expert testimony. The traditional elements of a
medical malpractice lawsuit are the duty to conform to a certain
standard, a failure to conform to the required standard, actual
injury or damage, and a legally sufcient causal connection between
the conduct and the injury.
f
Medical Negligence as It Applies to Vaccination Decisions
The basic scenarios that could potentially give rise to a claim or
lawsuit are where (1) a patient that is not vaccinated contracts the
disease for which vaccination was forgone; or (2) a patient experi-
ences an AE attributed to a vaccination later considered unnecessary
by the client. In either case, the plaintiff would be required to have
expert testimony that the defendants professional judgment under
the specic circumstances was a departure from the standard of care
and the cause of the injury to the dog. Although such claims do
occur, the risk of a lawsuit is considered low and can be mitigated
through effective, documented communication with the client.
Consent Versus Informed Consent
Consent is the giving of permission, approval or agreement.
Consent can be expressed or implied, written or verbal, docu-
mented or not. A veterinarian should understand regulations
relative to obtaining or documenting consent in states where they
practice, as a states practice act or regulations may address nec-
essary documentation of client consent.
g
Informed consent is consent based upon the disclosure of the
material risks of a proposed treatment or procedure and potential
alternatives, including the risk of no treatment.
h
The legal doctrine
of informed consent developed as human medicine evolved from
a paternalistic profession to one that recognizes the importance
of a patients self-determination. It is based upon the theory that
a competent human being has the right to determine what is done
with their body. To date, most states and provinces have not
formally addressed the question of applying informed consent law
Veterinary Practice Guidelines
JAAHA.ORG 23
to veterinarians. There are, however, a few states and provinces
with reported court decisions addressing the application of the
doctrine of informed consent to veterinary practice in some
fashion.
i
Additionally, there are a few states and provinces where
the veterinary practice act and/or implementing regulations in-
corporate either the doctrine of informed consent or elements of
it, and the American Association of Veterinary State Boards has
developed a model practice act that recommends to states the
incorporation of the requirement to obtain informed consent by
board regulation.
j
However, within the US there remains ongoing
debate about whether informed consent law should be applied to
veterinary practice. This is not the case with Canada, where the
incorporation into veterinary practice is readily accepted, either
by regulation or convention. Some within the veterinary com-
munity advocate forgoing use of the term informed consentfor
other terms while incorporating risk communication elements in
an analogous manner. The intent here is not to advocate for or
against the doctrine of informed consent or its particulars. Rather,
it is to acknowledge that allegations of a failure to obtain consent
or informed consent, historically common in physician medical
malpractice litigation, are not uncommon in complaints against
veterinarians as well. Therefore, it is prudent to understand the
issue and to understand that one of the best deterrents to an
informed consent lawsuit (or other legal action for that matter) is
effective communication with clients.
Documentation of Consent
Documentation of consent discussions is always helpful if there is
ever need to defend a veterinarians actions. Such documentation
could include a note in the chart that such a discussion took place
(with or without co-signature by the client); a note in the chart that
in addition to discussion, a specic client handout was given
k
;oruse
of a consent form signed by the client. Although defense lawyers like
more documentation, the task for practitioners is to determine the
method that best suits their practice and level of risk tolerance.
Where consent forms are used, the more general the language
used, the less helpful the documentation may prove in court;
conversely, the more specic the language, the more helpful to the
defense of a case. However, the practitioner should have a medi-
cally or scientically defensible basis for making any representa-
tions in a consent document. If precise numbers cannot be
justied, then more general statements are preferable.
Medical Record Documentation (AAHA
Accreditation Standards)
At the time of vaccine administration, the following information
should be recorded in the patients permanent medical record:
·Vaccines recommended for this patient
·Date of vaccine administration
·Identity (name, initials, or code) of the person administering
the vaccine
·Vaccine name, lot or serial number, expiration date, and man-
ufacturer of vaccines actually administered
·Site and route of vaccine administration
·Any concurrent medications/therapy
·Future recommended vaccinations
AEs should be recorded in a manner that will alert all staff
members during future visits. Consent should be documented
in the medical record to demonstrate that relevant information
was provided to the client and that the client authorized the
procedure.
Part II: Vaccination of Shelter-Housed Dogs
The AAHA Canine Vaccination Task Force developed vaccination
guidelines to facilitate the efforts of individuals responsible for
purchasing vaccines, administering vaccines, and/or developing
vaccination policy for shelter-housed dogs. The objective of writing
vaccination guidelines for shelter-housed dogs is to provide es-
sential recommendations to reduce, or eliminate when possible,
the risk of infectious disease outbreak or illness in shelter animals.
The Task Force recognizes that unique stafng and cost constraints
may preclude the ability of all animal shelters to implement these
Guidelines fully. However, the guidance provided in this section
is intended to provide a basis for developing and implement-
ing a rational vaccination program for animal shelters because
these dogs are at particularly high risk of exposure to infectious
disease.
The time and effort dedicated to controlling infectious
diseases among shelter-housed dogs is only one of many variables
in the complex shelter medicine and husbandry equation. The
recommendations provided here attempt to address shelter-
unique issues as they pertain to rational selection and use of
vaccines. Other important factors, such as population density,
ventilation, sanitation, staff training, etc., must be taken into
consideration when implementing an infectious disease control
plan.
Denition of a Shelter Environment
As used in the context of the Canine Vaccination Guidelines, an
animal shelter is a holding facility for homeless animals, usually
awaiting adoption, rescue, or reclaim by owners. In general, animal
shelters are predominantly characterized as a random source
population of dogs, as well as other animal species with a largely
unknown health and vaccine history, high population turnover,
24 JAAHA | 47:5 Sep/Oct 2011
and signicant potential for relatively high levels of infectious
disease risk.
Within this broad denition, however, there is wide variation.
The term shelterencompasses situations ranging from sanctu-
aries that possess a stable population to facilities that admit
dozens or even hundreds of animals per day to rescue and foster
homes that care for multiple litters or individuals at any given
time. Just as the appropriate vaccine strategy varies with each
individual pet, there is no one-size-ts-all strategy for vaccinating
shelter animals. Shelters should interpret these Guidelines in light
of the infectious disease risk and turnover rate within their own
populations.
Special Considerations of a Shelter Vaccination Program
The relatively high likelihood of disease exposure in most shelters
and the potentially devastating consequences of infection neces-
sitate a clearly dened shelter vaccination program with exacting
requirements. It is necessary to dene not only what vaccines are
appropriate, but also when vaccines should be administered with
respect to shelter entry, which animals are candidates for vacci-
nation, and how and by whom vaccines should be administered,
including record keeping and documentation of AEs. For vaccines
that offer signicant protection against common and severe in-
fectious diseases, the appropriate vaccination program may be one
that is more aggressive than is generally indicated in private
practice. Such a program may include, for example, vaccinating
dogs at the short end of the suggested intervals or at a relatively
early age.
With the use of vaccines at shorter intervals or in an expanded
population, it is also important to minimize the vaccines given to
those that are clearly indicated by the immediate and signicant
disease risks. Vaccines are often administered to stray dogs not
legally belonging to the shelter and may be given by lay staff under
indirect veterinary supervision. These considerations make it even
more crucial to develop a vaccine program that minimizes the risk
of vaccine-induced adverse reactions. Furthermore, cost differ-
ences that are trivial for one individual become signicant when
multiplied by thousands of doses. Therefore, only those vaccines
that demonstrate a clear benet against common and signicant
shelter diseases should be used. Adopters should be encouraged to
discuss an individually tailored vaccination program with their
own veterinarian after adoption.
Vaccination Guidelines for Shelters
Core Vaccines for Shelter-Housed Dogs
Vaccines for shelter use are categorized for pet dogs, as core
and noncore (optional) (Table 2). A number of other vaccines
discussed in the following are not recommended. Although the
Task Force acknowledges that variable shelter circumstances
make it impractical to provide universally applicable recom-
mendations, those vaccines categorized as core are essential vac-
cines that should be administered to all dogs at the time of entry
(CDV, CPV-2, CAV-2, IN Bb 1CPiV) or at the time of release
(RV).
51,7477
It is recommended that all dogs be vaccinated for rabies before
release from a shelter. If a long-term stay is anticipated or for
shelters where virtually all dogs will be adopted, rabies vaccine
should be administered on intake with the other core vaccines. The
earliest age at which rabies vaccine should be given is 12 wk, and it
is recommended that it be given at a site on the body different than
where the CDV, CPV-2, CAV-2 vaccines are administered. At open-
intake shelters, rabies vaccine should be administered at the time of
release. Although ideally vaccines should be given at least 2 wk
apart to avoid vaccine interference, the public health benetof
ensuring rabies vaccination before release is considered to out-
weigh the small risk of interference in this case. If state or local
requirements prevent issuance of a rabies certicate for vaccines
administered at the shelter (e.g., due to lack of veterinary su-
pervision), vaccination for the purpose of legal recognition and
licensing should be repeated at the owners veterinarian 24wk
later. Unless a certicate documenting previous rabies vaccination
is available, it should be assumed that previous vaccination has
not been received, and revaccination 1 yr later will be required.
69
Noncore Vaccines for Shelter-Housed Dogs
The CIV vaccine may be recommended (noncore) in selected
shelters located within endemic communities or in shelters that
transport dogs to or from communities considered to be endemic
for canine inuenza. This is a killed vaccine that requires two
doses be given at least 2 wk apart. Immunity is expected 1 wk after
the second dose. Therefore, even in shelters located within
endemic communities, the benet of this vaccine will be limited
if exposure cannot be prevented before onset of protection or
in dogs unlikely to stay long enough to receive the full series of
vaccines.
78,79
Vaccines Not Recommended for Use in the Shelter Environment
The vaccines listed in the not recommended category are for
diseases that do not represent a signicant threat to the population
of dogs residing in shelters, would not provide protection because
there is inadequate time for immunity to develop, or that have
limited efcacy against clinical disease. Among the various canine
vaccines licensed for use within the US, the following vaccines
are not recommended for routine use in shelter-housed dogs:
Veterinary Practice Guidelines
JAAHA.ORG 25
TABLE 2
2011 Canine Vaccination Guidelines for Shelter-Housed Dogs
Vaccine Initial Vaccination Revaccination (if indicated) Comments
CDV 1CAV2 1CPV2
Note: Use of a combination
CDV vaccine 1CAV-2 1CPV-2
vaccine with or without MLV
CPiV is recommended.
Killed (inactivated)
virus vaccines are not
recommended. Administer
SQ or IM
Administer a single dose immediately
before or at the time of admission
to all dogs unless there are veterinary
records showing the dog has been
vaccinated at 18–20 wk of age
or older with these core vaccines.
Alternatively, if the dog is 18–20 wk
of age or older and tested positive for
antibody to CDV and CPV-2, it would
not be necessary to vaccinate.
Minimum age: It is recommended
that vaccine not be administered to
shelter dogs ,4 wk of age.
Puppies (#18 wk of age): Revaccination
every 2 wk is recommended until
18–20 wk of age.
Dogs (#18–20 wk of age):
Revaccinate at 1 year of age then
revaccinate at 3 or more year intervals
as for pet animals as long as the dog
remains in the facility.
Core
·When feasible, puppies should be housed separately from
adult dogs, regardless of their vaccination status. All
MLV-CPV-2 vaccines available today are expected to provide
immunity from disease caused by any field variant recognized
today (CPV-2a, -2b, and -2c). All current CDV vaccines are
expected to provide immunity from disease caused by any
of the current variants of CDV viruses.
·MDA, if present, can interfere with immunization up to
16–18 wk of age. When distemper risk is high, inoculation
with the rCDV and measles/distemper vaccines have been
shown to protect puppies with MDA 2 wk earlier than the
MLV CDV vaccines. The MLV or rCDV vaccine should be used
when dogs are 16–18 wk or older, as both are highly effective
in the absence of MDA. Because it is often difficult to know the
exact age of puppies and because MDA are often higher in shelter
puppies, they may still be sufficient to block immunization at
14–16 wk in a small percentage of puppies. Therefore, when
feasible, shelter puppies should receive a final vaccine when
estimated to be 18–20 wk of age.
·Once the vaccine has been reconstituted and kept at room
temperature, the dose should be administered within 1 hr to
avoid inactivation of the vaccine virus, especially MLV CDV
vaccine.
Intranasal Bb 1CPiV. Use of a
combination (bivalent) INl MLV
(avirulent) Bb 1MLV
CPiV, vaccine is recommended,
with or without CAV-2. Administer
IN only. Do not
administer SQ or IM.
Administer a single dose immediately
before or at the time of admission.
Vaccine can be administered as early
as 3–4 wk of age (see manufacturer’s
administration recommendations). Do not
administer SQ or IM.
Dogs #6 wk of age: For best results,
an additional dose is recommended
after 6 wk of age at a
minimum vaccination interval of 2 wk.
Dogs .6 wk of age: Administer a
single intranasal dose every 6–12
mo as indicated. Do not
administer SQ or IM
Core
·Administration of MLV (avirulent) IN Bb by the SQ or IM route
can lead to severe reactions, including death.
·Onset of protective immunity after initial IN vaccination occurs
within 72 hr; vaccines can reduce the severity of disease but
will not entirely prevent canine respiratory disease complex.
·Use of a trivalent IN vaccine that also contains MLV CAV-2
should be considered in shelter-housed dogs when the 2-way
IN fails to provide acceptable protection.
Parenteral Bb Administer SQ. This
vaccine is not effective if
administered
by the IN route.
Administer the first dose at the time of
admission. Administer a 2nd dose
2 wk later if still in the facility.
(see comments).
Regardless of the dog’s age, 2 doses,
2 wk apart, are required to induce
immunity unless previously
vaccinated within the past 12 mo.
Dogs that have previously received a
2-dose initial vaccination
series or a booster vaccination
within the past year require only
a single dose at the time
of admission.
Parenteral Bb vaccine is recommended only as an alternative
when it is not possible or not feasible to administer an
INl vaccine (above). Note: In previously unvaccinated dogs,
a single dose of parenterally administered vaccine will not
immunize. Immunity is expected 7–10 days after
administration of the 2nd dose.
·The parenteral Bb vaccine does not include protection
against parainfluenza virus.
(Table continues)
26 JAAHA | 47:5 Sep/Oct 2011
leptospirosis; canine coronavirus; canine Lyme borreliosis (Lyme
disease); Crotalus atrox (rattlesnake) vaccine; parenterally adminis-
tered Bb (see Table 2 for exception); and parenterally administered
CPiV. Because most of these vaccines are killed (inactivated) and,
therefore, require two doses at least 2 wk apart, use of these vaccines
is viewed as impractical and unnecessary in most shelter-housed dogs.
Vaccination Recommendations for Specic Cases
in the Shelter Environment
Dogs with a Documented Vaccination History
at Time of Admission
There is no compelling reason to administer vaccines to an in-
dividual dog at the time of admission to a shelter if clear docu-
mentation conrms current vaccination administered after the age
of 16 wk is provided. The following is the minimum information
acceptable as documenting proof that a valid vaccination has been
administered:
·Proprietary name of product
·Manufacturer name
·Serial/lot number
·Date vaccine was administered (at least month and year)
·Expiration date of vaccine administered
·Signature of a licensed veterinarian
This information should be associated with a medical record
that clearly describes the dog in question. If any of this information
is not available at the time of admission or cannot be associated with
a formal record for the dog, then immediate vaccination is indicated.
Long-Term Shelter-Housed Dogs
It is recommended that all dogs entering a long-term care facility
(or any dog entering a shelter for which a long-term stay is
anticipated) be inoculated with all core vaccines, including ra-
bies vaccine, at the time of admission to the facility. If a dog is
routinely exposed to the outdoors, then noncore (optional)
vaccines should be considered (as for pet dogs), depending on
the dogsriskprole.
Because it can be difcult or impossible to determine whether
young dogs (,4 mo of age) have received any vaccines at all,
implementation of an initial series (CDV, CPV-2, CAV-2 [IM,
SQ], Bb, and CPiV [IN]), beginning as early as 4 wk of age (as
early as 34 wk of age for IN administered vaccines), may be
indicated. Parenterally administered core vaccines should not be
administered before 6 wk of age. When it is the decision of the
facility to initiate the series (i.e., puppy shots) to an individual
dog, then the recommended vaccines should be administered at
2 wk (rather than 3 or 4 wk) intervals until the dog reaches
$16 wk of age.
TABLE 2 (continued )TABLE 2 (continued )
Vaccine Initial Vaccination Revaccination (if indicated) Comments
RV 1 yr. Use of a killed
(inactivated) monovalent,
single dose vaccine is
recommended. Administer
SQ or IM.
Administer 1 dose at the time of release
from the facility. Dogs may be vaccinated as
early as 12–16 wk of age depending
on local regulations. If a long-term stay
is anticipated, administer 1 dose on
entry to the facility.
Revaccinate 1 yr after initial vaccination
and then at 3 yr intervals with
a 3 yr rabies vaccine as
for pet animals as long as the
dog remains in the facility.
Core: recommended for all dogs before release from shelter
·Unless valid (signed) documentation of prior rabies vaccine
administration is available, administration of a rabies
vaccine is indicated for all dogs leaving the facility,
regardless of age. Revaccination 1 yr later is required
by most jurisdictions.
·If local, state, or provential law does not permit issuance
of rabies certificate for vaccines given at the shelter,
vaccination can be repeated by the owner’s veterinarian
2–4 wk after leaving the shelter.
·Single dose vials are preferred to reduce the risk of
contamination and ensure proper mixing and dosage
of antigen and adjuvant.
CIV. A killed 2 dose
vaccine. Administer
SQ or IM.
Administer 2 doses 2 wk apart,
with the first dose given before or
immediately upon intake. Vaccine
can be administered as early as
6 wk of age. Two doses must be
given to provide immunity.
Revaccination with the 2nd dose
should occur 2 wk after the first.
For those dogs in long stay
shelters, annual revaccination is
recommended.
Noncore
·Do not vaccinate a dog unless it is possible to give the
initial 2 doses 2 wk apart, as 1 dose has not been shown
to provide any benefit.
·This vaccination should be considered for shelters in
endemic communities or those that transport dogs
to or from these locations.
Veterinary Practice Guidelines
JAAHA.ORG 27
In the event that an individual dog resides in the facility long
enough to justify booster vaccination, it is recommended that the
revaccination schedule recommended for individual pets be fol-
lowed (Table 1).
29,51,74,76,8082
Vaccination of Pregnant Dogs in the Shelter Environment
Shelter personnel may be faced with the dilemma of whether
to vaccinate a pregnant dog upon admission to a facility. His-
torically, vaccination during pregnancy has not been recom-
mended in small animal medicine. This is due in part to the
paucity of data concerning vaccine safety and efcacy during
gestation and the expectation that, in nonimmune pregnant
bitches, MLV vaccine can cause fetal damage or death.
22,30,49
When the immunity of the dog is unknown, however, the risk
of maternal, fetal, and neonatal infection with eld strain virus
must be weighed against the risk of vaccination. If nonimmune
pregnant dogs are likely to be exposed to eld strain infection
with pathogens such as parvovirus or distemper, serious illness
or death of both bitch and fetuses may result. Unless facilities
are available to completely isolate them from other dogs,
pregnant bitches should either be vaccinated or not remain in
the shelter.
Vaccination of Sick Dogs in the Shelter Environment
As with pregnant dogs, veterinary medicine has advised against
vaccination during illness, due to concerns about suboptimal
protection, or worse, vaccine-induced illness. The decision to
administer or delay vaccination because of a current illness
depends on the severity of disease and its etiology.
The shelter environment does not usually permit the luxury of
isolating dogs and delaying their vaccination until concurrent
illness is resolved. Therefore, vaccination is advised upon ad-
mission for dogs with minor illness (e.g., otitis, dermatitis, upper
respiratory tract infection with or without fever) or injuries.
Vaccination of dogs with severe signs of disease ideally should be
delayed whenever feasible. However, unvaccinated shelter dogs
may develop more severe disease if left unvaccinated, and thus
would be at greater risk of dying. In the high-risk shelter envi-
ronment, vaccination of sick dogs with core vaccines should be the
rule with very few exceptions.
51
Contact Information for Biologics Manufacturers
Company Name
Tech Services
Phone (US)
Tech Services
Phone (Canada)
Boehringer Ingelheim
Vetmedica Inc.
866–638–2226 800–263–2425
Merck Animal Health 800–224–5318 800–361–2353
Merial 888–637–4251
(ext. 3)
888–637–4251
(ext. 57320)
Pfizer Animal Health Inc. 800–366–5288 800–461–0917
Red Rock Biologics 866–897–7625 No Canadian
number provided
Appendix
PDF form for adverse event reporting (US).
PDF form for adverse event reporting (CANADA).
m
2011 AAHA Canine Vaccination Guidelines
Frequently Asked Questions
The frequently asked questions (FAQs) that follow are based on
questions raised by practicing veterinarians regarding the use and
selection of vaccines in dogs. The FAQs have been arranged in four
categories: Adminisration of Vaccines, Vaccine Products, Vaccine
Adverse Events, and Legal Issues Pertaining to Vaccination. Many
of the FAQs included have been derived from, or are edited ver-
sions of, FAQs developed by the World Small Animal Veterinary
Associations (WSAVA) Vaccine Guidelines Group (VGG). AAHA
wishes to acknowledge the WSAVA and the VGG for their con-
tributions and support.
Due to the nature of the questions listed in the following,
scientic studies and publications supporting each response may
not be available. However, the reader is reminded that the FAQ
answers represent a consensus of opinion from Task Force mem-
bers and are based on scientic literature in companion animal
immunology and infectious diseases. Although some of the rec-
ommendations outlined may be viewed as controversial, these are
not intended to be requirements. They are only intended to provide
guidance on key points of concern to practicing veterinarians.
Implementation of any of these recommendations is left to the
discretion of the practicing veterinarian.
Questions Related to Administration of Vaccines
1. Can different types of vaccines be mixed in the same syringe?
One should never mix different vaccine preparations in the
same syringe unless specied on the label.
2. Is it safe to inject different vaccines (not part of a single com-
mercial product) into the same dog at the same appointment?
Different vaccine types can be injected into the same patient,
but they should be injected into separate sites that are
drained by different lymph nodes. For example, if a combination
MLV (attenuated) vaccine (such as, CDV 1CAV-2 1CPV-2)
is administered SQ over the left shoulder, a killed (inacti-
vated) leptospirosis or rabies vaccine could be administered
SQ over the right shoulder.
28 JAAHA | 47:5 Sep/Oct 2011
3. To reduce the risk of an adverse reaction, can the volume of an
individual dose of parenteral vaccine be reduced for adminis-
tration to small breed dog?
The volume (e.g., 1.0 mL) as recommended by the manu-
facturer generally represents the minimum immunizing
dose; therefore, the total amount should be given to induce
a protective immune response.
4. Is it necessary to administer the entire volume of an IN kennel
coughvaccine?
Although administration of the entire dose and/or volume
of an intranasal vaccine is recommended, loss of some
reconstituted vaccine is expected (induced sneezing or
drainage) after administration. IN vaccines are attenuated
(MLV and/or avirulent live bacteria) and, as such, will infect
and replicate after administration (see FAQ 7). Loss of some
vaccine volume after proper administration is not expected
to compromise the local immune response.
5. Should the large dog (e.g., Great Dane) be injected with the
same volume of vaccine as the small dog (e.g., Chihuahua)?
Unlike pharmaceuticals (the dose of which is usually based on
weight), a vaccine dose is not based on volume per body mass
(size), but rather on the minimum immunizing dose (inacti-
vated vaccine) or the minimum infectious dose (attenuated
vaccine). Therefore, the entire dose should be administered as
directed by the manufacturer. Administering less than the
prescribed dose may not induce a protective immune re-
sponse (see also FAQ 3).
6. Should vaccine be administered to the anesthetized patient?
Doing so is not generally recommended. There is a small
risk that a postvaccinal hypersensitivity reaction may lead to
vomiting and an increased risk of aspiration. Also, some
anesthetic agents may modulate the immune response to
a vaccine.
However, in the event there is limited opportunity to ad-
minister a vaccine (e.g., spay and neuter programs), admin-
istering vaccine during, or immediately on recovery from,
anesthesia is acceptable.
7. Whats the difference between an infectiousvaccine and
anoninfectiousvaccine?
An infectiousvaccine is capable of replicating within the
host after administration. All modied live (attenuated)
viralandbacterialvaccinesandvirus-vectoredrecombi-
nant vaccines are infectious (e.g., MLV-CDV, IN Bb, and
rCDV).
Anoninfectiousvaccineisnotcapableofreplicating
within the host after administration. All killed (inacti-
vated) viral vaccines (e.g., rabies, CIV) and bacterial vaccines
(e.g., Leptospira spp., Lyme, Bordetella) and certain sub-
unit recombinant (rLyme OspA) vaccines are noninfectious.
8. Should a pregnant dog be vaccinated?
Vaccination with MLV (attenuated) and/or killed (inacti-
vated) vaccines during pregnancy should be avoided, if pos-
sible, to avoid potential injury to the fetus. There are
exceptions, especially in shelters, where vaccination would
be advised if the pregnant dog has never been vaccinated
and there is risk of exposure to a highly pathogenic virus
(e.g., CDV, CPV-2).
9. Does glucocorticoid treatment in the dog interfere with core
vaccine immunity during the primary or secondary (booster)
vaccination programs?
Studies in dogs suggest that short-term glucocorticoid treat-
ment, even at high doses (2.5 mg/kg) before or at the time of
vaccination does not have a signicant suppressive affect on
antibody production. However, it is reasonable to revacci-
nate $2 or more weeks after long-term therapy has ended,
especially when treatment occurred during administration
of the initial series of core vaccines.
10. Should vaccine be administered to pets that are receiving im-
munosuppressive drugs or cytotoxic therapy (other than gluco-
corticoids) (e.g., for cancer or autoimmune diseases)?
Manufacturers only recommend administration of vaccine
to healthy dogs. Dogs receiving immunosuppressive chemo-
therapy should not be vaccinated. Doing so may result in
a suboptimal immune response or may aggravate (reacti-
vate) an immune-mediated illness.
11. Can vaccine be administered weekly to puppies that may be at
high risk of exposure to an infectious pathogen?
Ideally, vaccines should not be given more often than every
2 wk, even if different vaccines are administered. Transient
downregulation of the immune system after administration
may interfere with subsequent vaccine administration for up
to 10 days. However, in certain situations (short-term stay in
shelters), it may be necessary to vaccinate at intervals of ,2wk.
12. When should the last vaccine dose of core vaccines be given
during the initial (puppy) vaccine series?
The last dose of core vaccine, regardless of the number
of doses previously administered, should be given at 14 to
16 wk of age or older (see Tables 1 and 2).
13. Vaccines are indicated for administration to healthy dogs only.
In locations that require dogs to be vaccinated against rabies, is
the veterinarian still required to administer vaccine to a dog
that has a chronic or systemic illness?
Rabies vaccination requirements for dogs are generally de-
ned by state or provincial law; however, local municipalities
Veterinary Practice Guidelines
JAAHA.ORG 29
(counties or cities) may impose rabies vaccination require-
ments that are more restrictive, but never less restrictive,
than those dened by the state or province.
Some, but not all, government agencies grant rabies vac-
cination waiver authority to veterinarians in the event an
individual dog is determined by the veterinarian to be
sufciently ill that vaccination should be delayed. Physical
examination and medical record documentation of the
illness is generally required; it is the responsibility of
the owner and the veterinarian to ensure the dog is revac-
cinated when or if the underlying medical condition is
resolved.
Note: any dog that has exceeded the stipulated rabies
revaccination (booster) interval is not legally consid-
ered immunized against rabies, although a rabies vacci-
nation waiver may be in effect. Due to the potential
implications of a biting incident involving a dog that is
not legally considered as immunized against rabies, the
owner should be involved in the decision-making process
of whether to vaccinate, and the veterinarian should doc-
ument the discussion in the patients medical record.
Veterinarians practicing in locations where rabies vacci-
nation waiver authority is not specically dened should
contact the state or provincial Veterinary Medical Board
or the Department of Health for guidance on this issue
before vaccinating a dog with a medical condition that, in
the veterinarians judgment, precludes administration of
rabies vaccine.
14. What would happen if an avirulent live IN Bb vaccine is
administered by the SQ or IM route?
IN Bb vaccine contains live, avirulent gram-negative bacte-
ria that, if parenterally administered, can cause abscess for-
mation at the injection site and may culminate in death
associated with bacterial replication, bacteremia, and release
of hepatotoxic proteins.
15. Should a noninfectious (inactivated, killed) parenteral Bb vac-
cine be administered by the IN route?
No. Doing so will not stimulate a protective immune re-
sponse to Bb.
16. Have vaccination site recommendations been stipulated for the
dog as they have for the cat?
Vaccination guidelines for the dog do not specify injection
site recommendations. Veterinarians are strongly encour-
aged to document the inoculation site and vaccine type in
the patients medical record.
17. Can different vaccine brands (different manufacturers) be ad-
ministered to the same patient at the same time?
Doing so is safe and effective. However, vaccines should not
be mixed within the same syringe or administered in the
same location.
18. Should a disinfectant (e.g., alcohol) be applied to the injection
site before administering a vaccine?
Because disinfectant might inactivate an MLV (attenuated)
product, and is not known to provide any benet to the
patient, doing so is not generally recommended.
19. Will a single dose of infectious (attenuated, avirulent, modied
live, recombinant viral vectored) core vaccines provide any
benet to the dog?
In the absence of MDA (especially dogs $16 wk of age),
onedoseofaMLV(attenuated)caninecorevaccine
(CDV, CPV-2, CAV-2) is likely to provide long-term
immunity.
20. When administering the initial doses of killed vaccines that
require two doses to immunize (e.g., Leptospira, Lyme disease,
CIV), and the dog does not return for the second dose within
6 wk after the rst dose, is the dog considered to be immunized?
Noninfectious (inactivated, killed) vaccines require two
doses on initial vaccination. The rst dose primes the im-
mune system, the second dose immunizes. If a second dose
is not given within 6 wk of the rst, two additional doses,
administered from 2 to 6 wk apart, are recommended. Rabies
vaccine is the exception.
21. For how long can a reconstituted MLV vaccine remain at room
temperature without losing activity?
At room temperature (e.g., 60808F), some of the more
sensitive MLV vaccines (e.g., CDV) may lose their ability
to immunize after 23 hr. It is recommended that MLV
vaccines be discarded if kept at room temperature for
$1 hr after reconstitution.
22. What is the recommendation for revaccinating a dog with an
infectious (modied-live, attenuated, or recombinant) core
vaccine if that patient has not been properly revaccinated
within the recommended time period stipulated for that
vaccine?
A single dose of infectious (MLV, attenuated, or recombi-
nant viral vectored) core vaccine is considered sufcient to
‘’boostimmunity in a dog that has previously been vacci-
nated (e.g., $3 yr). Because a single dose of MLV or
recombinant core vaccine will both prime and immunize,
it is not necessary to administer a series of two or three
doses to boostthe patients immunity. Note: The reason
for administration of an initial infectious core vaccine se-
ries to puppies is to administer at least one dose that will
avoid interference by MDA.
30 JAAHA | 47:5 Sep/Oct 2011
23. Does severe nutritional deciency affect the immune response
to vaccines?
It has been shown that certain severe deciencies of vita-
mins and trace minerals (e.g., Vitamin E/Se) can interfere
with the development of a protective immune response to
certain vaccines, especially in puppies. Known or sus-
pected nutritional deciencies should be corrected by ap-
propriate nutritional supplementation, and the dog should
be revaccinated to ensure there is adequate protective
immunity.
24. If a puppy fails to receive colostrum (MDA) during the rst
3 days of life, will it derive any passive antibody protection
from the dam?
A puppy receives little or, most likely, no immune protec-
tion in the absence of colostrum. Approximately $95% of
passive antibody for a newborn puppy is obtained from the
colostrum, which is absorbed via the intestine into the sys-
temic circulation for up to 72 hr after birth.
25. If a puppy fails to receive colostrum (MDA), should it be
vaccinated during the rst few weeks of life?
To reduce the risk of the MLV core vaccine causing an
adverse reaction, colostrum-deprived puppies should not
be vaccinated until $4 wk of age. In the absence of
MDA, certain modied live vaccines, when administered
to colostrum-deprived pups ,2 wk of age, can infect the
central nervous system (e.g., CDV, CPiV) and/or the heart
(CPV-2), and can cause disease.
26. How can colostrum-deprived puppies be protected against the
core diseases?
Articial colostrum can be orally administered if the puppy
is ,3 days old and has never been fed a protein diet. Arti-
cial colostrum can be formulated by administering a mix-
ture of 50% milk replacer (e.g., Esbilac
n
or other similar
product) and 50% immune serum (preferably from the dam
or other well vaccinated dog living in the same environment
as the dam). Note: If a puppy received protein (e.g., milk
replacer) orally or is $3 days of age, serum from a well-
immunized adult dog can be given SQ or intraperitoneally
(absorption via the intestinal tract does not occur in dogs
that are .3 days of age). Alternatively, citrated plasma can
be administered intravenously. Depending on size of the
dog, approximately 310 mL of serum or plasma should
be administered twice daily for up to 3 days.
Questions Related to Vaccine Products
27. Will the administration of vaccine to a puppy bindor other-
wise deplete MDA, leaving the dog susceptible to infection?
Vaccination in the presence of MDA can interfere with the
vaccine but will not deplete, or measurably alter, the level of
protection a puppy derives from passive (maternal) immunity.
28. Is it possible to immunize puppies in the presence of MDA?
Although MDA may interfere with any vaccine, multiple
factors inuence the ability of any vaccine to immunize
a dog in the presence of MDA; for example, antibody titer
of dam, nursing history, concentration of MDA in the puppy,
age of the puppy, health status of the puppy, the type of
vaccine, and virulence and concentration of the vaccine
antigen, etc. Limited studies demonstrated that the viral
vectored rCDV vaccine and MV can immunize puppies
in the presence of CDV MDA about 2 wk earlier than
aMLVCDVvaccine.Note: High levels of MDA can still
interfere with MV and recombinant (viral vectored) CDV
vaccines.
29. Can MDA interfere with active immunization by both
modied-live (attenuated) and killed (inactivated) vaccines?
To some extent, all vaccines, both noninfectious (inactivated,
killed) and infectious (attenuated, avirulent, modied live,
recombinant viral vectored) vaccines, are susceptible to MDA
interference.
Noninfectious vaccines require a minimum of two initial doses
(26 wk apart) to immunize: the rst dose primesthe im-
mune response; the second dose immunizes. In dogs vacci-
nated at ,12 wk of age, there is risk that MDA will interfere
with (block) the rst dose of inactivated vaccine. In such cases,
the priming immune response does not occur. The second
dose, therefore, would not immunize.
30. It has been suggested that certain canine infectious (attenu-
ated, avirulent, modied live, recombinant viral vectored) core
vaccines need only be administered twice, with the last dose at
an age as young as 1012 wk. Is that accurate?
Some canine vaccines are recommended (label) for ad-
ministration of two initial doses: the rstdoseatapprox-
imately 6 wk and a second dose at 10 wk of age. Serious
reservations exist about discontinuing the initial core vaccine
series in any dog before 1416 wk of age. No combination
core vaccine product currently available will immunize an
acceptable percentage of puppies when the last dose is
given at 1012 wk of age.
It is strongly recommended that the last dose in the initial
series be administered at 1416 wk of age, regardless of the
product used or the number of doses administered earlier.
If the initial vaccination series is discontinued by 1012
wk, it is recommended that an antibody titer to CDV and
CPV be obtained to ensure the animal develops an
Veterinary Practice Guidelines
JAAHA.ORG 31
immune response. During the interim, the individual dogs
exposure to other dogs should be strictly limited.
31. When two vaccine types (MLV and killed) are available for the
same antigen, is there any benet to administering both vac-
cines, parenterally and topically (e.g., Bb or parainuenza
virus), to an individual dog at the same appointment?
Doing so is not considered harmful. Benecial effects as-
sociated with simultaneous administration of an IN and
parenteral vaccine for the same antigen (e.g., Bb and para-
inuenza virus) have not been clearly documented.
32. Are there advantages to administering either IN Bb or paren-
teral Bb vaccine?
Studies have shown that both vaccine types, parenteral and
IN, mitigate the severity of clinical signs among dogs chal-
lenged and/or exposed to Bb.
Initial vaccination using an IN Bb vaccine provides rapid
onset (within 3 days) protective immunity after a single
dose. Initial vaccination with parenteral (cellular antigen
extract) Bb vaccine requires administration of two doses,
at least 2 wk apart, then an additional 710 days before
immunity develops.
Dogs vaccinated with IN Bb had signicantly lower cough
scores and shed signicantly fewer challenge organisms
(challenged 63 days postvaccination) compared with dogs
vaccinated with parenteral Bb. Therefore, in high-risk envi-
ronments (e.g., shelters), IN Bb vaccine, in combination with
parainuenza virus vaccine, is recommended over parenteral
vaccine.
Use of parenteral vaccine is recommended for use in those
patients that aggressively resist IN vaccination.
33. How long after administration of the core vaccines does it take
for a healthy dog that does not have MDA to develop immu-
nity that will prevent severe disease?
This is dependent on the dog, the vaccine, and the vaccine
virus. After a single dose of core vaccine:
·MLV and rCDV: immunity to CDV begins within hours
after administration. This very early immunity does not
prevent infection but does prevent severe disease (espe-
cially neurologic), and death, if administered 23 days
before exposure.
·MLV CPV-2: immunity to CPV-2 develops in as few as 3
days and is usually protective (based on challenge studies)
by 5 days postvaccination.
·MLV CAV-2: parenterally administered CAV-2 vaccine pro-
vides protection against canine hepatitis virus infection
(CAV-1) and is expected to induce protective immunity
by 57 days postvaccination. In contrast, IN administered
CAV-2 vaccine (combined with Bb and CPiV vaccine) pro-
vides protection against CAV-2, one of the pathogens associ-
ated with canine infectious respiratory disease and is likely to
induce protective immunity within 3 days postvaccination.
34. How efcacious are the core vaccines in the properly vaccinated
puppy/dog?
Ninety-eight percent or more of dogs vaccinated at 1416
wk of age with a MLV CPV-2, a MLV CAV-2, and a MLV
or rCDV vaccine should develop a protective immune re-
sponse after parenteral administration of a single dose.
35. Are there new variants of CDV in the eld for which current
CDV vaccines do not provide protective immunity?
All of the current infectious CDV (MLV and recombinant)
vaccines provide protection against all the known isolates
(variants) of CDV.
36. Do the current infectious CPV-2 vaccines provide protection
from disease caused by the new variant CPV-2C?
All current infectious CPV-2 vaccines induce a protective
immune response (e.g., antibody response) that provides
long term ($4 yr) protection from all known CPV-2 var-
iants (2a, 2b, and 2c). Protection was documented after
both natural and experimental challenge.
37. Can parvovirus vaccines (e.g., CPV-2) be administered orally?
CPV-2 vaccines, when administered orally, will not immu-
nize. The most effective route of administration is paren-
teral (SQ or IM) vaccination.
38. Are serum antibody titers useful in determining vaccine
immunity?
Serum antibody titers correlate with protective immunity
against CDV, CPV-2, and CAV-1 immunity (induced by
CAV-2 vaccine). RV antibody titers can be determined
for individual patients (certicated laboratories only) and
do reect an immune response to vaccination; however, at
the present time, such titers generally are not used to es-
tablish protective immunity in an individual dog. Likewise,
postvaccination rabies titers generally cannot be used to
replace the requirement for revaccination.
Serum antibody titers currently available are of limited or
no value as a measure of protective immunity for the non-
core vaccines. See also page 17 of the Guidelines for addi-
tional information on serum antibody titers.
39. When a noninfectious (inactivated, killed) Leptospira vaccine
(bacterin) is administered, should it be a product containing
2 serovars or 4 serovars.
There is little or no cross protection induced by the var-
ious Leptospira serovars. Therefore, it is recommended that
for dogs deemed to be at risk for exposure, a four-way
32 JAAHA | 47:5 Sep/Oct 2011
leptospirosis vaccine should be administered annu-
ally after the initial puppy series of two doses (see also
Table 1 ) .
40. Do Leptospira vaccines provide the same degree of long-term
immunity as core vaccines?
Leptospira vaccines provide short-term immunity (e.g., up
to 12 mo) and the efcacy may be ,70% for certain sero-
vars. The immunity among the serovars varies and immu-
nity varies among vaccinated dogs. Persistence of detectable
antibody after vaccination will often be only a few months
and immunologic memory for protective immunity may
only last approximately 1 yr. Therefore, when a dog is at
risk for leptospirosis and has not been revaccinated during
a period of $2 yr, two doses 26 wk apart should be given
instead of a single dose.
41. How many doses of vaccine should be given to a dog presented
for their initial vaccine series if the patient is older than 1416
wk of age?
Most manufacturers recommend administering two doses,
34 wk apart. When using noninfectious (inactivated,
killed) vaccine, two doses are essential to immunize (ra-
bies is the only exception). However, when administering
an infectious modied-live attenuated or a recombinant
distemper virus vaccine to healthy dogs older than 1416
wk of age, 1 dose is considered sufcient to immunize.
42. Can infectious (attenuated, avirulent, modied live, recombi-
nant viral vectored) vaccines be administered to dogs already
infected as a means of treatingthe clinical disease or short-
ening the course of infection?
Administering vaccine to clinically ill patients as a means of
treating the disease is neither effective nor is it recommended.
By the time clinical signs develop, the infection is well
established. However, in a kennel or shelter situation, be-
causedogsareinvariousstagesofexposure,vaccination
of the entire group will often prevent or end a signicant
outbreak.
43. What is nonsterile immunity?
Many vaccines serve only as an aid in the prevention of
clinical signsassociated with exposure to pathogenic
viruses/bacteria. Such vaccines do not prevent infection,
may not completely prevent development of clinical signs
and, may not completely prevent shedding (CIV, CAV-2,
parenteral Bb, and leptospirosis are vaccine examples), but
should prevent or reduce disease.
44. What is sterile immunity?
Some vaccines induce protective immunity, and prevent
infection, thus clinical signs will not occur following
exposure. These vaccines induce sterileimmunity (e.g.,
CPV and CDV).
45. Will the current kennel coughvaccines provide protection
from disease caused by the CIV?
None of the current vaccines used to prevent Bb, para-
inuenza virus, or CAV-2 (causes of canine infectious respi-
ratory disease; also called kennel cough), provide any
protection against CIV.
46. Is there a vaccine available to aid in the prevention of disease
caused by CIV?
There are licensed vaccines available that are designed to aid
in the prevention of inuenza in dogs caused by the H3N8
inuenza virus. The products are adjuvanted killed vac-
cines that, like all noninfectious (inactivated, killed) vac-
cines, requires two initial doses, administered parenterally,
given 24 wk apart. Immunity develops approximately
1 wk after the second dose. This vaccine is monovalent and
is not currently available in combination with any other
vaccines.
47. Can nosodes (holistic preparations) be used to immunize pets?
Nosodes cannot be used for the prevention of any infectious
disease. They do not immunize because they do not contain
antigen, which is required for the development of cell me-
diated and/or humoral immunity.
Questions Related to Adverse Reactions to Vaccines
Note: Vaccine adverse events are signicantly underreported in
veterinary medicine. The USDA, the CFIA, and the vaccine
manufacturers strongly encourage reporting of any known, or
suspected, adverse event following administration of a veterinary
vaccine. Reporting instructions can be found on page 20 of the
guidelines.
48. Is there a risk of over-vaccinating a pet (e.g., injecting it too
often, or using vaccines that are not required for the specic
pet)?
Vaccines are biologic products; administration should be
tailored to the needs of the individual dog and should never
be given needlessly. All vaccines have the potential to cause
adverse reactions following administration. See page 19 of
the guidelines for additional discussion on vaccine AEs.
49. Are certain vaccines or combinations of vaccines more likely to
cause adverse reactions than others?
Although the development of an adverse reaction may be
dependent on the genetics of the dog (e.g., small breeds),
certain vaccines have a higher likelihood of producing ad-
verse reactions, especially reactions caused by Type I (ana-
phylaxis due to IgE) and/or Type III (Ag-Ab complex)
Veterinary Practice Guidelines
JAAHA.ORG 33
hypersensitivities. See page 19 of the guidelines for addi-
tional discussion on vaccine AEs.
50. Should dogs with a history of acute postvaccinal adverse re-
action (hives, facial edema, anaphylaxis, etc.) or immune-
mediated diseases (such as IMHA) receive booster vaccines?
There may be risk in doing so. If the vaccine known or
suspected to have caused the adverse reaction is an attenu-
ated (MLV) core vaccine (e.g., CDV or CPV-2), a serological
(serum antibody) test can be performed. If the dog is found
to be positive, the dog is considered immunized and revac-
cination is not necessary.
If the vaccine is a noncore vaccine (e.g., Leptospira,Bordetella,
Lyme bacterin), revaccination is discouraged (serum anti-
body titers are not reective of the patients immune status).
If rabies vaccine is implicated as the cause of an adverse event,
appropriate authorities should be consulted to determine
whether rabies vaccination can be exempted (waivered).
In the event vaccination is deemed necessary, administration
of an alternative product (by a different manufacturer or
different type of vaccine) may be helpful. However, there is
no guarantee that a dog will not develop an adverse event if
a different product is administered.
Hypersensitivity reactions are not necessarily linked to the
immunizing antigen; in fact, the sensitizing protein(s) are
often linked to constituent proteins associated with the
manufacturing process (bovine serum albumin, tissue culture
antigens). See page 19 of the guidelines for additional discus-
sion on vaccine AEs.
51. Can vaccines cause autoimmune diseases?
Vaccines themselves do not cause autoimmune disease, but
in genetically predisposed dogs, vaccination may induce
immune-mediated disease. Note: immune-mediated disease
can also be linked to infection, oral or parenteral drug ad-
ministration, and possibly other environmental factors.
52. Is there any risk to clientele or veterinary staff, especially im-
mune compromised individuals, subsequent to intranasal vac-
cination with an avirulent live (attenuated) Bb vaccine?
It is possible for transient shedding of attenuated Bb to
occur following intranasal administration. There are two
known reports identifying a temporal relationship between
the identication of human Bordetella infection and expo-
sure to attenuated live Bb canine vaccine, one of which was
in an immunocompromised patient.
53. How common are postvaccination adverse reactions?
There are no reliable data that provide information on the
true incidence of postvaccination adverse events (reactions)
in companion animals. In the US and Canada, there is no
vaccine adverse event database maintained that is available
for public review. Although serious postvaccinal adverse
reactions among dogs are considered to be uncommon,
a prior history of a known or suspected postvaccinal adverse
event should be taken into consideration when recommend-
ing vaccines for individual patients
Current studies have shown that, among dogs, the risk of an
acute-onset (within 3 days) adverse reaction is greatest
among small breed dogs receiving multiple vaccines at the
same appointment. Such practices should be avoided (see
page 22 of the guidelines).
54. Are there dogs that cannot develop an immune response to
vaccines?
Although uncommon, it does appear that some dogs have an
inability to respond to specic vaccine antigens. Dogs vacci-
nated with a CDV-CPV-2-CAV-2 may respond to two of the
constituent vaccines but not a third. This is attributed to
a genetic trait; dogs affected in this way are called nonre-
sponders. Genetically related (same family or same breed)
dogs will often share this nonresponsiveness. If the dog is
a nonresponder to a highly pathogenic agent, like canine
parvovirus virus (estimated at 1/1,000 dogs), the dog may
die if infected. In contrast, if the individual dog is a non-
responder to a pathogen that rarely causes death (Bb),
clinical signs may develop following exposure despite prior
vaccination, and the dog is not likely to die, but it may
become a carrier.
55. Does the adverse reaction risk of a noninfectious (inactivated,
killed) vaccine (e.g., acute hypersensitivity) persist in the indi-
vidual patient for an extended period or is it of short duration?
Immune memory associated with acute (type I) hypersen-
sitivity (IgE) to a leptospira bacterin may be sustained for
at least 4 yr (as determined by intradermal testing) even
though the protective immune response (IgG) may only
last a year.
56. Is there a vaccination program that could be recommended for
those owners only wanting the least number of vaccines possi-
ble or for those dogs that are not likely to be seen again by
a veterinarian?
The vaccination protocol that includes the minimum num-
ber of vaccines yet still provides a reasonable opportunity
to immunize the dog would be: a single dose of a combined
infectious (attenuated, avirulent, modied live, recombi-
nant viral vectored) CDV, MLV CPV-2, with MLV CAV-2,
administered at 16 wk of age or older, plus a rabies vaccine
at the same time (but inoculated at a separate site on the
body).
34 JAAHA | 47:5 Sep/Oct 2011
AAHA wishes to acknowledge the openness, assistance, and en-
couragement of the veterinary biologics manufacturers. AAHA
would also like to thank Tara da Costa, DVM, from the Canadian
Centre for Veterinary Biologics and Douglas C. Jack, Solicitor, for
providing the Canadian perspective included in these Guidelines.
In addition, the association would like to express its gratitude to
Nancy E. Clough, DVM, PhD, DACVM, and Christopher Chase,
DVM, PhD, DACVM, both of whom served as external reviewers
for the Guidelines, and to Scott McVey, DVM, PhD, DACVM, and
the American College of Veterinary Microbiologists for their assis-
tance in identifying Drs. Clough and Chase.
Questions Related to Legal Issues
57. How should communications between the veterinarian and
client associated with vaccinations differ from communications
associated with other medications?
The issues related to consent and client discussions relative to
risk/benetproles do not differ in their essence between
vaccines and other medications. That does not mean that
every practitioner must have the same level of discussion with
every client for every vaccine or other medication. Wherever
there are meaningful risk/benet considerations, it is strongly
recommended to include the client in the decision making
process.
58. Is it necessary to explain the risks associated with every individ-
ual vaccine during each visit in which vaccinations are admin-
istered?
It is advisable to have an initial vaccine discussion about
vaccines with the client that is documented and more thor-
ough, followed by periodic and less extensive discussion at
subsequent vaccination. If the practitioner believes that the
risk/benetprole for the various antigens administered in
a visit is essentially the same, they could be discussed as a
group. If an individual antigen was considered to carry
asignicantly different risk/benetprole, then it could
be addressed individually. At subsequent vaccination appoint-
ments, it is a good idea to briey remind the client of the
clinical approach taken to vaccination and ask if the client
has any questions. Additionally, if over time there is a
change in the perceived risk/benetprole, then additional
discussion with the client is indicated. Finally, practitioners
must be in a position to know their clients and identify
those that will benet from more discussion.
59. Can a veterinarian be held legally liable for withholding a core
vaccine from a dog with immune mediated disease that later
succumbs to one of the diseases prevented by the core vaccines?
The risk should be low if the client is involved in the process
and the discussion is documented in the chart. For example,
a note in the chart that: (1) a discussion was held with the
client regarding the relative risks of exacerbating the patients
autoimmune disease or other adverse event versus the poten-
tial for disease/death if the patient contracts a disease for which
vaccination has been foregone, (2) that the client chose not to
vaccinate, and (3) that the client was given an opportunity to
ask questions, would go a long way to reducing legal risk.
60. What is a reasonable degree of documentation for risk/benet
discussions with clients concerning vaccination?
There is no one size ts all answer to this question. The
Guidelines purposefully do not say document consent in
this manner ..