ACIP Updates Typhoid Vaccination Recommendations

Laurie Barclay, MD

March 26, 2015

Typhoid vaccine should not be given routinely in the United States, according to updated recommendations from the Advisory Committee on Immunization Practices (ACIP) published in the March 26 issue of the Morbidity and Mortality Weekly Report. However, typhoid vaccination continues to be recommended for US travelers to certain countries.

"In 1994, [ACIP] approved recommendations for typhoid vaccination, stating that typhoid vaccine is indicated for U.S. travelers to certain countries, close contacts of chronic carriers, and certain laboratory workers," write Brendan R. Jackson, MD, from the Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, and colleagues.

"The updated recommendations contain new data on the epidemiology of typhoid fever and vaccine effectiveness and safety."

Specific recommendations include the following:

•  Travelers to countries with high prevalence of typhoid and recognized risk for exposure to Salmonella serotype Typhi should be vaccinated against typhoid, even if they are staying with friends or relatives or only traveling for a short time.

•  The list of available typhoid vaccines no longer includes the discontinued parenteral whole-cell vaccine.

•  Otherwise, there are no substantive changes to previous ACIP typhoid vaccine recommendations.

•  The two typhoid vaccines currently available in the United States are parenteral Vi capsular polysaccharide vaccine and oral live-attenuated Ty21a vaccine, both of which are acceptable for use.

•  Clinicians should warn travelers to consume only safe foods and beverages because typhoid vaccines offer only moderate protection, and large inocula of Salmonella serotype Typhi can overcome vaccine-induced protection.

•  Household contacts of chronic carriers, defined as persons with excretion of Salmonella serotype Typhi in urine or stool for 1 year or more, should be vaccinated.

•  Microbiologists and other laboratory staff routinely exposed to cultures of Salmonella serotype Typhi or specimens containing it should also be vaccinated.

•  With the exception of these groups, routine typhoid vaccination is not recommended in the United States.

"Risk is greatest for travelers who have prolonged exposure to possibly contaminated foods and beverages, although short-term travelers are also at risk," the report authors conclude. "Most travel-associated typhoid fever cases in the United States occur among travelers who are visiting friends or relatives; many travelers in this group do not seek pre-travel health care. Multidrug-resistant strains of Salmonella serotype Typhi have become common in many regions, and cases of typhoid fever that are treated with drugs to which the organism is resistant can be fatal."

The authors have disclosed no relevant financial relationships.

Morb Mortal Wkly Rep. 2015:64:305-308. Full text


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