From the CDC: New Country-Specific Recommendations for
Pre-Travel Typhoid Vaccination
Katherine J. Johnson, MPH,∗Nancy M. Gallagher, BA,∗Eric D. Mintz, MD,†
Anna E. Newton, MPH,‡§Gary W. Brunette, MD,∗and Phyllis E. Kozarsky, MD∗
∗Travelers’ Health Branch, Division of Global Migration and Quarantine, National Center for Emerging and Zoonotic
Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA;†Waterborne Disease Prevention Branch,
Division of Foodborne, Waterborne and Environmental Diseases, National Center for Emerging and Zoonotic Infectious
Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA;‡Enteric Diseases Epidemiology Branch, Division of
Foodborne, Waterborne and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers
for Disease Control and Prevention, Atlanta, GA, USA;§Atlanta Research and Education Foundation, Inc., Decatur, GA, USA
Typhoid fever continues to be an important concern for travelers visiting many parts of the world. This communication provides
updated guidance for pre-travel typhoid vaccination from the US Centers for Disease Control and Prevention (CDC) and
describes the methodology for assigning country-specific recommendations.
impact travelers.1,2While the risk to travelers in high-
transmission areas, such as the Indian subcontinent, is
well established, epidemiologic data at the subregional
or country level are limited for many areas.3–5The
lack of information on disease risk makes the decision
of whether to recommend typhoid vaccination for
travelers to these areas, a challenging one for health
country-specific recommendations about travel-related
diseases through its website (www.cdc.gov/travel),
which receives over 27 million unique page views per
year and is THB’s most comprehensive communication
tool.6Historically, recommendations were provided
on a regional basis only. In 2007, CDC transitioned
to country-specific recommendations, but limitations
yphoid fever is a serious illness and a disease
of public health significance that continues to
Summary findings on this work were also presented, by the
same authors, at the 12th conference of the International
Society of Travel Medicine, May 8–12, 2011, in Boston, MA,
USA, as a poster.
Corresponding Author: Katherine J. Johnson, MPH,
Travelers’ Health Branch, Division of Global Migration and
Clifton Rd. NE, MS E-03, Atlanta, GA 30333, USA. E-mail:
recommendations being applied to all countries within
To reflect important epidemiologic differences that
may impact travel-related disease risks, we systemati-
cally reviewed all country-specific recommendations. In
2010, THB met with CDC experts in enteric diseases
to begin this process for all country-specific typhoid
recommendations for travelers. This team was formed
to review and update these recommendations through
an iterative consensus process over a period of months.
Sources and Methods
We examined a total of 238 destinations worldwide
(including countries, special administrative areas, non-
self-governing territories, island groupings, and other
overseas territories), divided into 19 regions, that are
featured on the Travelers’ Health website. For all
regions, destination-specific data were collected from
a variety of sources, including published literature on
the incidence of typhoid and paratyphoid fever by
country or region; US national surveillance for travel-
related cases; country-level incidence data published
on the websites of WHO regional offices, Ministries
of Health, or their equivalent; and the Global
Foodborne Infections Network country databank, a
WHO-sponsored voluntary reporting system.7
After reviewing comparable published estimates
on global typhoid incidence, the authors developed
incidence brackets for each destination, dividing them
into three categories: low if <10/100,000 cases/year;
© 2011 International Society of Travel Medicine, 1195-1982
Journal of Travel Medicine 2011; Volume 18 (Issue 6): 430–433
CDC Recommendations for Typhoid Vaccination
medium if 10–100/100,000 cases/year; and high
if >100/100,000 cases/year. Because country-level
incidence data do not always adequately represent a
traveler’s risk for acquiring typhoid fever, incidence
classifications were compared to CDC’s national
surveillance database of travel- and domestically
acquired typhoid fever cases in the United States.8All
were matched to their reported countries of exposure
to determine where travelers are most often exposed to
typhoid fever. A total of 2,077 records were reviewed.
Countries were ranked by the cumulative number of
imported cases during this timeframe as a proportion of
all cases reported to CDC. This step was included to
identifyany ‘‘hotspots’’for typhoidexposure among US
travelers that may not be reflected in endemic incidence
rates. It was not possible to calculate incidence rates
because we could not accurately determine the number
of US travelers exposed. Therefore, we did not set
numeric cut-offs for low, medium, and high rates of
compared the endemic incidence rate to the proportion
of imported cases among US travelers to assign a
destination-specific risk category for each country.
These destination-specific risk categories were then
used to inform destination-specific recommendations
for pre-travel typhoid vaccination. Based on consensus
among CDC experts in THB and enteric diseases, it
was decided that vaccination would be recommended
for destinations falling into the medium- and high-risk
categories, while the low-risk category would result in a
recommendation not to vaccinate.
Results and Discussion
As a result of this review, the typhoid vaccine
recommendation remained unchanged for 212 (89%)
of the 238 destinations. Changes did occur in
the Eastern European and Middle Eastern regions,
where 26 countries for which typhoid vaccine was
previously recommended based on presumed risk,
were downgraded to the low-risk category (Figure 1).
These destinations are Albania, Armenia, Azerbaijan,
Belarus, Bosnia and Herzegovina, Bulgaria, Croatia,
Cyprus, Czech Republic, Estonia, Georgia, Hungary,
Israel, Kosovo, Latvia, Lithuania, Macedonia, Moldova,
Slovenia, and Ukraine.
53 domestically acquired typhoid cases, or 0.02/100,000
cases/year, were reported annually to CDC. For the
destinations in Figure 1, the country-specific incidence
rates ranged from 0 to 0.91/100,000 reported cases/year
with a median of 0.01/100,000 cases/year, well below
the low incidence ceiling of 10/100,000 cases/year.
Furthermore, only five cases (0.2%) of typhoid
imported into the United States during 1999–2008
were potentially linked to these destinations. Two of
Figure 1 CDC revised recommendations for pre-travel typhoid vaccination.
J Travel Med 2011; 18: 430–433
Johnson et al.
these ill travelers reported visiting a single country
of exposure, Hungary and Russia, respectively. The
remaining three ill travelers reported visiting multiple
countries worldwide, making the actual country of
exposure difficult to determine: the first of these three
travelers reported visiting Austria, Germany, Hungary,
and the Czech Republic; the second visited India, the
Czech Republic, the UK, and Slovakia; the third visited
Afghanistan, India, and Russia.
While the risk behaviors of travelers and resident
populations are not directly comparable, these data
suggest that the overall risk of acquiring typhoid
during travel to these destinations is low. Factors
such as improved sanitation and water supply probably
contributed to these results, especially in countries
like Belarus, the Czech Republic, Estonia, and Poland,
which have reported increased access to improved water
sources in both urban and rural areas.9,10
providing destination-specific travel recommendations
for travelers. Our assessment focused on US travelers
and may not be widely applicable to travelers from
other parts of the world whose risk behaviors may
vary. We also chose to rely on internal CDC subject-
matter expertise, comprising several groups across the
agency, instead of employing the Delphi method and
engaging external global experts in a more formal
review process. For these reasons, we limited our
results section to the destinations with enough data
to support a change in recommendation. With limited
data for some parts of the world, input from global
partners would be valuable in future efforts to improve
destination-specific recommendations in these areas.
This communication attempts to make the process for
making recommendations more transparent, while also
recognizing that public health agencies with competing
priorities and limited resources may often need to
engage in iterative review processes that gradually
improve recommendations over time. The approach
outlined here serves as an interim solution, combining
CDC’s internal resources with externally available
literature and data sources, until a more comprehensive
follow-up review can be accomplished.
The guidance published on the CDC Travelers’
Health website is a tool to assist travel medicine
providers, but in no way replaces the individual
assessment of each traveler’s risk.11,12It is expected
that health care providers will conduct a pre-travel
consultation to assess how these recommendations
apply to individual travelers. Regardless of the risk
level for typhoid, the web pages for all destinations
contain recommendations about food and water
safety. As enteric infections for which no vaccines
are available, such as paratyphoid fever, become
increasingly prevalent among travelers, attention to
these basic food and water safety recommendations
remains an essential part of travel safety.
The change in recommendations for 26 Eastern
European and two Middle Eastern destinations is an
encouraging reflection of reduced disease risk due
to improvements in water and sanitation coverage.
However, the fact that pre-travel vaccination is still
recommended for 175 (74%) of 238 destinations
demonstrates that typhoidcontinues to remain a serious
risk to travelers in many parts of the world. While
reliable country-specific data remains limited in some
of the potential risk of acquiring typhoid fever during
travel by compiling and evaluating country-specific data
from a variety of sources instead of relying on regional
trends. Similar approaches could be used to strengthen
recommendations for other travel-related diseases.
The authors of this manuscript represent a multidis-
ciplinary team comprising many groups within CDC.
We gratefully acknowledge the following Branches and
individuals who assisted with this review: Ezra Barzi-
lay, Clive Brown, Stephanie M. Delong, C. Virginia
Lee, Kevin S. Liske, Benjamin L. Nygren, Katharine
A. Schilling, Amanda Whatley, members of the Trav-
elers’ Health Branch, Waterborne Disease Prevention
Branch, and Enteric Diseases Epidemiology Branch.
We also thankSusanne Karlsmose of the National Food
Institute, Technical University of Denmark, for provid-
ing data from the WHO Global Foodborne Infections
The findings and conclusions in this report are those of
the authors and do not necessarily represent the views
of the Centers for Disease Control and Prevention.
Declaration of Interests
The corresponding author guarantees the integrity of
the data and its analysis. Persons having a major part in
manuscript preparation are acknowledged.
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