Vaccine knowledge and practices of primary care providers of exempt vs. vaccinated children

Institute for Vaccine Safety and Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205, USA.
Human vaccines (Impact Factor: 3.64). 03/2008; 4(4):286-91. DOI: 10.4161/hv.4.4.5752
Source: PubMed
ABSTRACT
Compare vaccine knowledge, attitudes and practices of primary care providers for fully vaccinated children and children who are exempt from school immunization requirements.
We conducted a mailed survey of parent-identified primary care providers from four states to measure perceived risks and benefits of vaccination and other key immunization beliefs. Frequencies of responses were stratified by type of provider, identified by exempt versus vaccinated children. Logistic regression was used to calculate odds ratios for responses by provider type.
551 surveys were completed (84.3% response rate). Providers for exempt children had similar attitudes to providers for non-exempt children. However, there were statistically significant increased concerns among providers for exempt children regarding vaccine safety and lack of perceived individual and community benefits for vaccines compared to other providers.
The great majority of providers for exempt children had similar attitudes about vaccine safety, effectiveness and benefits as providers of non-exempt children. Although providers for exempt children were more likely to believe that multiple vaccines weaken a child's immune system and were concerned about vaccine safety and less likely to consider vaccines were beneficial, a substantial proportion of providers of both exempt and vaccinated children have concerns about vaccine safety and believe that CDC underestimates the frequency of vaccine side effects. Effective continuing education of providers about the risks and benefits of immunization and including in vaccine recommendations more information on pre and post licensing vaccine safety evaluations may help address these concerns.

Full-text

Available from: M. Patricia Dehart
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286 Human Vaccines 2008; Vol. 4 Issue 4286 Human Vaccines 2008; Vol. 4 Issue 4
Introduction
Immunizations have been remarkably successful in preventing
disease.
1,2
Yet the success of immunization programs has created a
paradox. When diseases are prevalent, the public has a fear of disease
and seeks prevention through immunization. When high levels of
immunization coverage are sustained, disease is reduced and public
attention shifts to concerns about vaccine safety rather than fear of the
diseases. When concerns about vaccine safety become widespread, a loss
in public confidence in vaccines
3
can result in a resurgence of disease.
4
Most parents follow the advice of their primary health care
providers (PHCP) and comply with state school immunization
requirements by fully vaccinating their children before school
entrance.
5,6
State laws requiring vaccination for school entry have
contributed to the success of the U.S. childhood immunization
programs.
7
Most states offer non-medical exemptions to school
immunization requirements. The rates of parents refusing vaccines
by claiming non-medical exemptions have been increasing in states
that make exemptions easily available to parents.
8
Vaccine safety
concerns were identified as the primary reason for vaccine refusal in
a recent Indiana measles outbreak.
9
We conducted a case-control study to determine why some
parents refused vaccines by claiming non-medical exemptions. We
surveyed parents of exempt (case) and vaccinated (control) elemen-
tary school children recruited from 112 private and public schools in
Colorado, Massachusetts, Missouri and Washington.
10
The primary
reason parents did not vaccinate their children was concern that
vaccines might cause harm (68.6%) or overload the immune system
(49.1%). Compared with parents of vaccinated children, parents of
exempt children were more likely to report low perceived vaccine
safety and efficacy, disease susceptibility and severity, and trust in
health care providers and government. Parents of vaccinated children
were more likely to report that their child’s PCHP were physicians
(93.9% vs. 75.8%, respectively); parents of exempt children were
more likely to report that their child’s PHCP were nurse practitioners
(7.4% vs. 2.7%, respectively) or complementary or alternative medi-
cine (CAM) providers (11.5% vs. 0.3% respectively).
Objectives: Compare vaccine knowledge, attitudes and practices
of primary care providers for fully vaccinated children and children
who are exempt from school immunization requirements.
Methods: We conducted a mailed survey of parent-identified
primary care providers from four states to measure perceived risks
and benefits of vaccination and other key immunization beliefs.
Frequencies of responses were stratified by type of provider, identi-
fied by exempt versus vaccinated children. Logistic regression was
used to calculate odds ratios for responses by provider type.
Results: 551 surveys were completed (84.3% response rate).
Providers for exempt children had similar attitudes to providers for
non-exempt children. However, there were statistically significant
increased concerns among providers for exempt children regarding
vaccine safety and lack of perceived individual and community
benefits for vaccines compared to other providers.
Conclusions: The great majority of providers for exempt chil-
dren had similar attitudes about vaccine safety, effectiveness and
benefits as providers of non-exempt children. Although providers
for exempt children were more likely to believe that multiple
vaccines weaken a child’s immune system and were concerned
about vaccine safety and less likely to consider vaccines were
beneficial, a substantial proportion of providers of both exempt
and vaccinated children have concerns about vaccine safety and
believe that CDC underestimates the frequency of vaccine side
effects. Effective continuing education of providers about the risks
and benefits of immunization and including in vaccine recommen-
dations more information on pre and post licensing vaccine safety
evaluations may help address these concerns.
*Correspondence to: Neal A. Halsey; Institute for Vaccine Safety; Johns
Hopkins Bloomberg School of Public Health; Department of International Health;
615 N. Wolfe Street; Room W5041; Baltimore, Maryland 21205 USA;
Tel.: 410.955.6964; Fax: 410.502.6733; Email: nhalsey@jhsph.edu
Submitted: 01/22/08; Accepted: 02/19/08
Previously published online as a Human Vaccines E-publication:
http://www.landesbioscience.com/journals/vaccines/article/5752
Research Paper
Vaccine knowledge and practices of primary care providers
of exempt vs. vaccinated children
Daniel A. Salmon,
1,2
William K.Y. Pan,
2
Saad B. Omer,
1,2
Ann Marie Navar,
2,3
Walter Orenstein,
4
Edgar K. Marcuse,
5
James Taylor,
6
M. Patricia deHart,
7
Shannon Stokley,
8
Terrell Carter
9
and Neal A. Halsey
1,2,
*
1
Institute for Vaccine Safety; and
2
Department of International Health; Johns Hopkins Bloomberg School of Public Health; Baltimore, Maryland USA;
3
Duke University; School
of Medicine; Durham, North Carolina USA;
4
Emory University; College of Medicine; Atlanta, Georgia USA;
5
Children’s Hospital and Medical Center; Seattle, Washington
USA;
6
University of Washington; Child Health Institute; Seattle, Washington USA;
7
Washington State Department of Health; Immunization Program; Olympia, Washington USA;
8
Centers for Disease Control and Prevention; National Center for Immunization and Respiratory Diseases; Atlanta, Georgia USA;
9
The PATH Malaria Vaccine Initiative; Seattle,
Washington USA
Abbreviations: PHCP, primary health care provider; CAM, complementary or alternative medicine; VIS, vaccine information statement
Key words: vaccines, primary care providers, parents, exemptions, school immunizations
[Human Vaccines 4:4, 286-291; July/August 2008]; ©2008 Landes Bioscience
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Vaccine knowledge/practices of PCPs of exempt versus vaccinated children
www.landesbioscience.com Human Vaccines 287
PHCPs greatly influence parents immunization decisions.
11
Cost,
12
PHCP perceptions of vaccine efficacy and safety,
12-14
missed
opportunities to vaccinate,
6,11,15-17
recognition of professional
organization recommendations,
18-20
and clinic characteristics
21-24
have been associated with parental decisions to vaccinate.
25-33
In
our study of exempt and vaccinated children, more than 90% of
parents reported receiving vaccine information from their childs
PHCP. The majority of vaccinated (89.5%) and exempt (63.9%)
parents reported their child’s PHCP was a good or excellent source
for vaccine information. Yet, the role of PHCP in impacting parents
who refuse vaccines has not been explored.
The aim of our study was to compare vaccine knowledge, atti-
tudes and practices of PHCP for children who are exempt from
school immunization requirements with PHCP for fully vaccinated
children.
Results
Of the 712 surveys mailed, 44 were returned without reaching the
provider (26 practices closed, five deceased providers, 13 providers
retired). Of the remaining 668 providers, 14 were not PHCPs. Of
the remaining 654 providers, 103 declined to complete a survey or
were lost to follow-up. Overall, 551 surveys were completed for an
84.3% response rate among eligible providers who received a survey.
Surveys were completed by 55 providers of exempt children (provider
identified by parent of one or more exempt child and no vaccinated
children), 64 mixed providers (provider identified by parent of one
or more exempt child and one or more vaccinated child), and 432
providers of vaccinated children (provider identified by parent of
one or more vaccinated child and no exempt children). Of the 551
providers who completed surveys, 389 providers were identified by
one parent, 88 providers were identified by two parents, and 74
providers were identified by three or more parents.
Providers for vaccinated children were more likely to have an MD
(87.9% vs. 74.1%, p = 0.01) and less likely to be DOs (13.0% vs.
5.3%, p < 0.01) than providers of exempt children. There was no
significant difference in the proportion of providers of exempt and
vaccinated children who were nurse practitioners (5.6% vs. 2.1%) or
naturopathic doctors (5.6% vs. 1.6%); however, the low number of
providers holding these degrees limited the power to detect a differ-
ence. The majority of providers of exempt and vaccinated children
were pediatricians (53.7% and 62.8%, p = 0.03), followed by family
medicine (44.4% and 33.3%, p = 0.01), and internal medicine (7.4%
and 1.9%, p = 0.07). The majority of providers of exempt (50.0%)
and vaccinated (58.8%) children were in a group practice (p-value =
0.44). Other office settings (not mutually exclusive) among providers
of exempt and vaccinated children included private practices (33.3%
and 32.6%, p = 0.44), two-physician practices (9.3% and 6.3%,
p = 0.04), HMOs (3.7% and 7.0%, p = 0.28) and other (community
health clinic, medical school clinic, etc.).
Providers of exempt children estimated that a lower proportion of
their patients aged 5–12 years were fully vaccinated based on ACIP/
AAP guidelines: 87% of providers of vaccinated children reported at
least 75% of their patients were fully vaccinated compared to 73% of
providers of exempt children. The vast majority (98.1%) of providers
of exempt and vaccinated children reported having a parent refuse a
vaccine. Providers of exempt and vaccinated children reported that
22.8% and 18.4%, respectively, of parents initiated questions about
risks of adverse events following vaccination (p = 0.18). Providers
of exempt and vaccinated children took the following actions when
a parent refused a vaccine (not mutually exclusive): noted refusal
(71.2% and 78.3%, p = 0.68), provided additional information
about the vaccine (73.1% and 78.1%, p = 0.07), required signature/
informed refusal document (28.8% and 38.5%, p = 0.12), offered
waiver for school laws (9.6% and 5.4% p = 0.25) and refused to care
for the child (7.7% and 9.2%, p = 0.12). The majority of providers
of exempt and vaccinated children reported giving parents VIS prior
to any immunization (64.0% and 71.4%, p = 0.07).
Concerns about the safety of vaccines was the most common
reason providers of exempt and vaccinated children reported as to
why some of their patientsparents had refused vaccines (86.3% and
75.7%, p = 0.27). Other reasons that providers of exempt and vacci-
nated children reported included not believing in vaccines (17.6%
and 21.4%, p = 0.21), alternative belief systems (13.7% and 22.4%,
p = 0.11), religious reasons (11.8% and 9.3%, p = 0.93), and lack
of concern about the diseases (7.8% and 7.6%, p = 0.28). A notable
proportion of providers of exempt and vaccinated children reported
that they would write a medical exemption so that a child could enter
school if the parent did not want to vaccinate his/her child even if
the child did not have a valid medical contraindication as defined by
ACIP, AAP or AAFP (24.5% and 14.6%, p = 0.40).
Providers of exempt children were slightly less likely to begin
to administer the vaccine series when it is recommended by ACIP
(47.1% vs. 53.3%, p = 0.01) or by AAP/AAFP (78.4% vs. 81.7%,
p = 0.01) and were slightly more likely than providers of vacci-
nated children to wait until the vaccine has been in universal use
for one year (17.6% vs. 14.3%, p = 0.03). A noticeable proportion
of providers of exempt and vaccinated children reported that they
would wait until the vaccine becomes a day care or school entry
requirement (13.7% and 15.6%, p = 0.24).
The majority of providers of exempt and vaccinated children
reported that the child and community benefit a moderate amount
when a child is fully vaccinated (Table 1). Providers of exempt chil-
dren were less likely than providers of vaccinated children to report
that the child, community, PHCPs, health insurance companies, and
state and federal government benefit a moderate amount or great
deal when a child is fully vaccinated (Table 1).
Providers of exempt children were less likely than providers of
vaccinated children to report high confidence in vaccine safety
(Table 2). Providers of exempt children tended to have more
concerns about vaccine safety and vaccine benefits (Table 3). For
example, 6.2% of providers for vaccinated children believed chil-
dren get more immunizations than are good for them compared
to 13.0% of providers of exempt children. Many of the beliefs that
differed among providers of exempt and vaccinated children related
to perceptions or beliefs regarding vaccine safety (Table 3).
Some concerns about vaccine safety were prevalent among both
groups of providers. For example, 19.2% of providers of exempt
children and 9.2% of providers of vaccinated children reported
concern that the CDC/ACIP underestimates the frequency of
vaccine side effects. Similarly, 13.0% of providers of exempt children
and 5.6% of providers of vaccinated children reported that they
cared for a child that had autism that they believe may have been
caused by vaccines (p = 0.04). When asked if they would vaccinate
a 15-month-old child who was due the following vaccines according
to the immunization schedule at that visit (MMR, DTaP, Hib, PCV,
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Vaccine knowledge/practices of PCPs of exempt versus vaccinated children
288 Human Vaccines 2008; Vol. 4 Issue 4
varicella, hepatitis B and influenza), a substantial proportion of
providers of both exempt and vaccinated children reported that they
would not administer all of these vaccines at that visit because: there
is an increased risk of adverse events with higher numbers of vaccines
(20.0% exempt and 12.8% vaccinated; p < 0.01) or they would not
want to overload the child’s immune system (16.0% exempt and
10.0% vaccinated; p = 0.12).
PHCPs with DO degrees perceived vaccine-preventable diseases
to be more serious than PHCPs with MD degrees (36.8% vs. 20.7%
serious or very serious; p = 0.02). PHCPs with DO degrees showed
significantly less confidence in vaccine safety compared to PHCPs
with MD degrees in all other constructs that were statistically signifi-
cant. For example, DOs were less likely than MDs to have a high
confidence in vaccine safety (76.3% vs. 88.4%; p = 0.03). PHCPs
with DO degrees were more likely than PHCPs with MD degrees
to agree or strongly agree with the following statements: children
get more immunizations than are good for them (13.9% vs. 5.6%;
p = 0.05); immunizations do more harm than good (8.1% vs. 1.7%;
p = 0.02); many of the reports of serious side effects from vaccines
are accurate (24.3% vs. 8.0%; p < 0.01); and the CDC/ACIP
underestimate the frequency of vaccine side effects (23.5% vs. 7.4%;
p < 0.01). PHCPs with DO degrees were less likely than PHCPs with
MD degrees to agree or strongly agree with the following statements:
immunizations are one of the safest forms of medicine ever developed
(67.6% vs. 85.2%; p < 0.01) and immunizations are getting better
and safer all of the time as a result of medical research (75.8% vs.
92.3%; p < 0.01).
Discussion
The results of our study indicate that most PHCPs identified by
exempt children have similar attitudes concerning vaccines as PHCPs
of non-exempt children. However, there were significant differences
in opinion for a minority of PHCPs in both groups. Overall, safety
as shown in Table 2 was very similar between the two groups, 88.9%
versus 93.9% reporting high vaccine safety. The most striking differ-
ence between PHCPs of exempt and vaccinated children related to
key safety immunization beliefs (Table 3). These findings suggest
that the knowledge, attitudes and practices of PHCPs may have an
important contributing effect on parental decisions to accept or forgo
vaccination.
Due to the cross-sectional nature of this study we could not assess
a temporal relationship and therefore we are not able to establish
causal relationships. While PHCPs may be directly influencing
parental decision making, parents could be selecting PHCPs who
share their vaccine attitudes and beliefs. Some parents who have
vaccine concerns and had poor experiences with their child’s PHCPs
Table 1 Proportion of health care providers reporting moderate amount or great deal of benefit when a child is fully
vaccinated, by provider type and associations between provider and parental responses
Who benefits when children receive Healthcare providers reporting moderate amount or great deal of benefit
all of the recommended vaccines
% Exempt
a
% Mixed
b
% Vaccinated
c
Odds ratio
d
95% CI
n = 55 n = 64 n = 432
Child 92.6 98.4 98.4 0.30e 0.10–0.85
Community 94.4 98.4 98.8 0.28 0.09–0.88
Primary care practitioner 64.2 51.6 68.2 0.59 0.39–0.90
Health insurance company 82.4 79.0 87.5 0.56 0.32–0.99
State and federal government 73.5 79.3 85.3 0.55 0.32–0.96
Vaccine companies 89.4 79.3 89.7 0.57 0.30–1.10
95% CI: 95% Confidence interval; Odds ratios in bold have p values 0.05;
a
Provider identified only by parents of exempt (unimmunized) children;
b
Providers identified by parents of exempt (unimmunized) and
vaccinated children;
c
Provider identified only by parents of vaccinated children;
d
Model results are based on binomial regression analysis accounting for within practice clustering of parents in a GEE framework. Odds
ratios include providers identified by both exempt and vaccinated parents in addition to providers only identified by either group;
e
Interpretation of Odds ratio = Health care providers identified by exempt children had
0.30 lower odds of reporting a child benefits a moderate amount or great deal when fully vaccinated compared with health care providers identified by vaccinated children.
Table 2 Proportion of health care providers with High perceived susceptibility and severity of disease and efficacy
and safety of vaccines, by provider type, and associations between provider and parental responses
Constructs Health care providers in high category
% Exempt
a
% Mixed
b
% Vaccinated
c
Odds ratio
d
95% CI
n = 55 n = 64 n = 432
Disease susceptibility
e
11.3 4.7 5.7 1.39 0.68–2.85
Disease severity
e
30.2 23.8 29.4 0.90 0.59–1.38
Vaccine efficacy
f
87.0 96.8 88.8 1.37 0.65–2.86
Vaccine safety
f
88.9 85.9 93.9 0.37 0.19–0.72
g
95% CI: 95% Confidence interval; Odds ratios in bold have p values 0.05;
a
Provider identified only by parents of exempt (unimmunized) children;
b
Providers identified by parents of exempt (unimmunized) and
vaccinated children;
c
Provider identified only by parents of vaccinated children;
d
Model results are based on binomial regression analysis accounting for within practice clustering of parents in a GEE framework. Odds
ratios include providers identified by both exempt and vaccinated parents in addition to providers only identified by either group;
e
Mean of 12 diseases ranging from 1.0–5.0, dichotomized by 1 to <4 and 4;
f
Mean of
9 vaccines for 12 diseases ranging from 1.0–5.0, dichotomized by 1 to <4 and 4;
g
Interpretation of odds ratio = health care providers identified by exempt children had 0.37 lower odds of reporting high perceived
vaccine safety compared with health care providers identified by vaccinated children.
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Vaccine knowledge/practices of PCPs of exempt versus vaccinated children
www.landesbioscience.com Human Vaccines 289
may have sought an alternative provider who was more open to their
concerns. Similarly, 9.2% of PHCPs of exempt children reported
that they would refuse to care for a child whose parents did not plan
on vaccinating that child. In such situations, these PHCPs may have
been responsible for the care of the child until the time of parental
vaccine refusal and then the parent found a different PHCP. Previous
studies have found that 39% of pediatricians would dismiss a family
who refused all vaccines and 28% of pediatricians would dismiss a
family for refusing some vaccines.
36
While many of the differences in attitudes, beliefs and practices
were statistically different between PHCPs of exempt and vaccinated
children, the absolute difference was often relatively modest. For
example, 92.6% of PHCPs of exempt children reported a moderate
or great deal of benefit from vaccines compared to 98.4% of PHCPs
of vaccinated children. In regression analysis, a highly significant
odds ratio was 0.30. Nonetheless, the vast majority of PHCPs in both
groups believed there was at least a moderate benefit from vaccines.
Similarly, 16.7% of PHCPs of exempt children and 4.2% of PHCPs
of vaccinated children reported concern that a child’s immune system
could be weakened by too many immunizations. The importance
of the prevalence of these beliefs goes beyond the odds ratio and
interpretation of our results must consider absolute risk as well as
risk ratios.
35
There was the potential for selection bias if responders differed
from non-responders in terms of immunization knowledge, attitudes
and practices and the type of child (exempt vs. vaccinated) they
cared for. Our high response rate should have minimized potential
selection bias.
Differences in provider knowledge, attitudes and practices were
observed between DOs and MDs. Our study was not designed to
analyze the difference by provider training. Nevertheless, the statis-
tically significant differences found in our study deserve further
Table 3 Proportion of health care providers agreeing or strongly agreeing to key immunization beliefs, by provider
type and associations between provider and parental responses
Health care providers agreeing or strongly agreeing with statement
% Exempt
a
% Mixed
b
% Vaccinated
c
Odds ratio
d
95% CI
n = 55 n = 64 n = 432
Children should only be immunized against serious diseases 39.6 57.8 43.2 1.25 0.91–2.01
Children get more immunizations than are good for them 13.0 15.9 6.2 2.28
e
1.56–5.10
A good diet is more important than immunization in 11.1 4.7 3.8 3.68 1.61–8.38
preventing infectious diseases
I am concerned a child’s immune system could be weakened 16.7 7.8 4.2 4.03 2.06–7.86
by too many immunizations
I am more likely to trust immunizations that have been 74.1 78.1 67.4 1.42 0.92–2.19
around for a while
Immunizations are one of the safest forms of medicine ever 76.9 76.2 82.2 0.75 0.48–1.18
developed
Immunizations are getting better and safer all of the time as 76.9 90.3 90.3 0.47 0.27–0.82
a result of medical research
Vaccines strengthen the immune system 64.7 58.7 69.4 0.55 0.36–0.85
For the overall health of a child, it is better for them to 15.1 4.8 4.0 4.08 1.90–8.76
develop immunity by getting sick than to get a vaccine
Healthy children do not need immunization 1.9 3.2 3.5 0.66 0.24–1.76
Immunizations do more harm than good 3.8 0.0 4.2 0.47 0.11–2.08
I am opposed to school immunization requirements because 9.4 9.5 5.2 1.88 0.83–4.23
they go against freedom of choice
I am opposed to school immunization requirements because 0.0 4.8 2.4 1.60 0.46–5.62
parents know what is best for their children
School immunization requirements protect children against 84.9 85.7 88.7 0.73 0.43–1.22
getting diseases from unimmunized children
Parents should be allowed to send their children to school 50.9 39.3 35.5 1.72 1.13–2.60
even if their child is not vaccinated
Breastfeeding protects children against vaccine preventable 7.8 0.0 1.9 2.14 0.60–7.65
diseases, such as polio, better than vaccination
I worry that many of the reports of serious side effects from 15.4 14.3 11.1 2.03 1.05–3.91
vaccines are accurate
I am concerned the CDC/ACIP underestimates the frequency 19.2 19.7 9.2 2.86 1.65–4.97
of vaccine side effects
95% CI: 95% Confidence interval; Odds ratios in bold have p values 0.05;
a
Provider identified only by parents of exempt (unimmunized) children;
b
Providers identified by parents of exempt (unimmunized) and
vaccinated children;
c
Provider identified only by parents of vaccinated children;
d
Model results are based on binomial regression analysis accounting for within practice clustering of parents in a GEE framework. Odds
ratios include providers identified by both exempt and vaccinated parents in addition to providers only identified by either group;
e
Interpretation of Odds ratio = health care providers identified by exempt children had
2.28 higher odds of agreeing or strongly agreeing that children get more immunizations than are good for them compared with health care providers identified by vaccinated children.
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Vaccine knowledge/practices of PCPs of exempt versus vaccinated children
290 Human Vaccines 2008; Vol. 4 Issue 4
exploration through study designs intended to assess differences in
provider training and vaccine attitudes and practices. We were not
able to explore differences between MDs and CAM providers because
of a lack of adequate number of the latter group. Vaccine knowledge,
attitudes and practices among CAM providers deserve further study.
Even among providers identified by vaccinated children, many
concerns about vaccine safety, concerns about the scientific cred-
ibility of CDC, and misconceptions about the capacity of the
immune system were prevalent. For example, 10% of providers of
vaccinated children reported that they believed that CDC/ACIP
underestimate the risks of vaccines, and nearly 6% believed that
they have cared for a child with autism as a result of vaccination.
These findings strongly suggest there is an urgent need for studies
to explore the origin of these concerns and find effective ways to
address them. Consideration needs to be given to such options as
expanding the information on pre and post licensing vaccine safety
evaluations in ACIP and AAP recommendations; having investiga-
tors not funded by pharmaceutical companies conduct vaccine safety
studies; having vaccine safety issues reviewed by independent groups
and/or agencies; improving provider education about immunization
and vaccine safety during professional schooling, clinical training,
and continuing professional education; training for clinicians on
risk communication, ongoing assessment of both the public’s and
providers vaccine safety concerns coupled with risk communication
messages targeting both these groups from sources each perceives as
credible; and additional studies and review articles that address the
vaccine safety concerns of health care providers.
Methods
In a previous case-control study to determine the reasons behind
vaccine refusal, we asked parents to provide the names and addresses
of up to 3 PHCP for their child at 2 and 5–6 years of age. In 2005,
we mailed a survey to these PHCP. Children were considered fully
vaccinated if they had received all vaccines required for school entry.
Children were considered exempt if they had claimed an exemption
for one or more vaccines. Parents of 391 exempt children and 976
vaccinated children supplied some contact information for PHCPs.
Parents named 806 different providers. Some mixed” providers were
identified by parents of vaccinated and exempt children. Provider
contact information was verified using online sources including
the AMA Physician Directory. Contact information for 94 (8%)
providers was unverifiable. A survey was mailed to 712 PHCPs via
Federal Express including a cover letter, the survey instrument, a
postage-paid return envelope, and a $20 cash incentive. Follow-up
included two letters, re-mailing the survey, and a phone call. This
study was approved by the Committees on Human Research at Johns
Hopkins University.
Survey instrument. Respondents were asked their most advanced
clinical degrees, their type of clinical practice and setting, and payment
method by estimated proportion of patients. Respondents were asked
to estimate the proportion of their patients aged 5–12 years who were
fully vaccinated by ACIP/AAP guidelines. Respondents were asked
if they have had a parent refuse vaccines; what proportion of parents
initiate questions about the risks of adverse events following vacci-
nation; if they give parents Vaccine Information Statements (VIS)
prior to any immunization; and what action(s) they take when a
parent refuses a vaccine. Respondents were asked what they consider
the most important reason parents have refused some vaccines; and
whether they would write a medical exemption for a parent who did
not want to vaccinate his/her child but did not have a valid medical
contraindication as defined by ACIP, AAP or AAFP.
Respondents were asked when they would be likely to regularly use
a new vaccine recommended for universal use in infancy, assuming
adequate supply and coverage by insurance or the Vaccines for
Children program. Respondents were asked if they would vaccinate
a 15 month old child in one visit who was due for the following
recommended vaccines: MMR, DTaP, Hib, PCV, varicella, hepatitis
B, influenza.
PHCPs were asked to use a five point Likert scale to identify
who benefits from vaccination (“not at all” to a great deal”); to
estimate the probability that an unimmunized preschooler would
contract an associated vaccine-preventable disease during a ten year
period (“impossible” to “very likely”); how serious it would be for
an 8-year-old to develop one of these diseases (“not at all serious”
to very serious”); how effective vaccines are in preventing children
from getting these childhood diseases (“not at all protective” to “very
protective”); and how safe the vaccine is (“dangerous” to “very safe”).
Respondents were asked to indicate their agreement/disagreement to
a series of questions relating to “key immunization beliefson a five
point Likert scale (“strongly disagree” to strongly agree”).
Data analysis. Frequencies for specific responses were calculated,
stratified by type of provider (exempt, mixed and vaccinated). To
explore differences between providers of exempt and vaccinated
children, we estimated logistic regression models using a Generalized
Estimating Equations framework (GEE-logistic).
34
Odds ratios are
the odds of a positive answer by a provider identified by an exempt
child compared with a positive answer identified by a provider of a
vaccinated child. A binomial framework allows for mixed providers
to contribute to the odds ratio calculation, weighted by the prob-
ability that the provider was identified by an exempt child.
General constructs for respondents’ assessments of disease suscep-
tibility and severity, and vaccine efficacy and safety were created
using the respondents mean Likert scores for all antigens/diseases
with a final score ranging from 1.0–5.0. Construct scores were
then dichotomized by 1.0–3.99 versus 4.0–5.0. Responses to “key
immunization beliefswere dichotomized by 1–3 (strongly disagree,
disagree, and neither agree nor disagree) vs. 4 and 5 (agree and
strongly agree) on the 5 point Likert scale.
Differences in attitudes and beliefs between PHCP with DO
degrees versus MD degrees were explored by running frequencies
of specific responses stratified by type of provider. Differences were
considered statistically significant based on the p-value obtained using
logistic regression with the attitude or belief variable as the outcome
variable and whether the provider had a MD or DO degree as the
independent variable. Differences between other types of providers
(i.e., MD vs. naturopathic physician or doctor of chiropractic) were
not explored as there were insufficient numbers of participants with
other degrees for meaningful analysis. Throughout all analyses,
p values 0.05 were considered statistically significant.
Page 5
©2008 LANDES BIOSCIENCE. DO NOT DISTRIBUTE.
Vaccine knowledge/practices of PCPs of exempt versus vaccinated children
www.landesbioscience.com Human Vaccines 291
Acknowledgements
Grants from CDC (#U01IP000032-02) and NIH training grant
(#K23AI059213).
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  • Source
    • "Contact information could not be found for 94 of these providers (8%). Surveys covering vaccine knowledge, attitudes, and beliefs were mailed in 2005 to 712 of these parent-identified providers [16]. The Committees on Human Research at Johns Hopkins University approved this study. "
    [Show abstract] [Hide abstract] ABSTRACT: Rates of delay and refusal of recommended childhood vaccines are increasing in many U.S. communities. Children's health care providers have a strong influence on parents' knowledge, attitudes, and beliefs about vaccines. Provider attitudes towards immunizations vary and affect their immunization advocacy. One factor that may contribute to this variability is their familiarity with vaccine-preventable diseases and their sequelae. The purpose of this study was to investigate the association of health care provider year of graduation with vaccines and vaccine-preventable disease beliefs. We conducted a cross sectional survey in 2005 of primary care providers identified by parents of children whose children were fully vaccinated or exempt from one or more school immunization requirements. We examined the association of provider graduation cohort (5 years) with beliefs on immunization, disease susceptibility, disease severity, vaccine safety, and vaccine efficacy. Surveys were completed by 551 providers (84.3% response rate). More recent health care provider graduates had 15% decreased odds of believing vaccines are efficacious compared to graduates from a previous 5 year period; had lower odds of believing that many commonly used childhood vaccines were safe; and 3.7% of recent graduates believed that immunizations do more harm than good. Recent health care provider graduates have a perception of the risk-benefit balance of immunization, which differs from that of their older counterparts. This change has the potential to be reflected in their immunization advocacy and affect parental attitudes.
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  • Source
    • "Although only disease severity and vaccine safety were statistically significant in our study, there was a positive association between parents and providers for all four constructs. Parental concern about the safety of routine childhood recommendations has grown in recent years and is today cited as one of the main reasons for delaying or refusing vaccination [2] [10] [11] [14]. As vaccine safety was the most highly associated construct between parents and providers it supports a potentially critical role that providers play in influencing parental belief. "
    [Show abstract] [Hide abstract] ABSTRACT: Health care providers influence parental vaccination decisions. Over 90% of parents report receiving vaccine information from their child's health care provider. The majority of parents of vaccinated children and children exempt from school immunization requirements report their child's primary provider is a good source for vaccine information. The role of health care providers in influencing parents who refuse vaccines has not been fully explored. The objective of the study was to determine the association between vaccine-related attitudes and beliefs of health care providers and parents. We surveyed parents and primary care providers of vaccinated and unvaccinated school age children in four states in 2002-2003 and 2005. We measured key immunization beliefs including perceived risks and benefits of vaccination. Odds ratios for associations between parental and provider responses were calculated using logistic regression. Surveys were completed by 1367 parents (56.1% response rate) and 551 providers (84.3% response rate). Parents with high confidence in vaccine safety were more likely to have providers with similar beliefs, however viewpoints regarding disease susceptibility and severity and vaccine efficacy were not associated. Parents whose providers believed that children get more immunizations than are good for them had 4.6 higher odds of holding that same belief compared to parents whose providers did not have that belief. The beliefs of children's health care providers and parents, including those regarding vaccine safety, are similar. Provider beliefs may contribute to parental decisions to accept, delay or forgo vaccinations. Parents may selectively choose providers who have similar beliefs to their own.
    Full-text · Article · Jul 2013 · Vaccine
  • Source
    • "Contact information could not be found for 94 of these providers (8%). Surveys covering vaccine knowledge, attitudes, and beliefs were mailed in 2005 to 712 of these parent-identified providers [16]. The Committees on Human Research at Johns Hopkins University approved this study. "
    [Show abstract] [Hide abstract] ABSTRACT: Rates of delay and refusal of recommended childhood vaccines are increasing in many U.S. communities. Children’s health care providers have a strong influence on parents’ knowledge, attitudes, and beliefs about vaccines. Provider attitudes towards immunizations vary and affect their immunization advocacy. One factor that may contribute to this variability is their familiarity with vaccine-preventable diseases and their sequelae. The purpose of this study was to investigate the association of health care provider year of graduation with vaccines and vaccine-preventable disease beliefs. We conducted a cross sectional survey in 2005 of primary care providers identified by parents of children whose children were fully vaccinated or exempt from one or more school immunization requirements. We examined the association of provider graduation cohort (5 years) with beliefs on immunization, disease susceptibility, disease severity, vaccine safety, and vaccine efficacy. Surveys were completed by 551 providers (84.3% response rate). More recent health care provider graduates had 15% decreased odds of believing vaccines are efficacious compared to graduates from a previous 5 year period; had lower odds of believing that many commonly used childhood vaccines were safe; and 3.7% of recent graduates believed that immunizations do more harm than good. Recent health care provider graduates have a perception of the risk-benefit balance of immunization, which differs from that of their older counterparts. This change has the potential to be reflected in their immunization advocacy and affect parental attitudes.
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