- Typhoid fever is caused by Salmonella typhi, an enteric gram-negative rod.
- The disease is common in developing countries with poor sanitation.
- Typhoid presents with fever, GI symptoms and leukopenia. It can be fatal if left untreated.
- Injectable: Polysaccharide vaccine
- Oral: Live attenuated bacterial vaccine
- Exact figures from large studie
- s are lacking, however, reported efficacy from various studies is in the range of 50-75%.
- It is important for travelers to recognize that getting vaccinated is not a substitute for being careful about edibles and beverages because the vaccine is not 100% effective.
Routine Vaccination:
Typhoid vaccination is usually not done in developed countries like US where Typhoid is relatively rare.
While Typhoid endemic countries especially in Asia will likely benefit from routine immunization against Typhoid, not many countries have included the vaccine in their routine immunization programs.
Typhoid vaccination is usually not done in developed countries like US where Typhoid is relatively rare.
While Typhoid endemic countries especially in Asia will likely benefit from routine immunization against Typhoid, not many countries have included the vaccine in their routine immunization programs.
At Risk Groups:
Vaccination is recommended for the following groups of people who are likely to be exposed to S. typhi.
Vaccination is recommended for the following groups of people who are likely to be exposed to S. typhi.
- Travelers to typhoid endemic areas. Ty21a vaccine should be administered at least 1 weak before expected exposure. Vi capsular vaccine should be administered at least 2 weeks before expected exposure.
- Close contacts of a documented typhoid carrier.
- Lab workers who may be exposed to S. typhi cultures or other possibly contaminated material.
Schedule:
- Vi capsular: single dose is required given IM. A booster dose is recommended every two years if the person continues to remain at risk. The vaccine is not for use in children younger than 2 years.
- Ty21a vaccine: 4 doses taken orally on alternate days (day 0, 2, 4, and 6). The whole course of 4 doses is to be repeated every 5years if the person continues to remain at risk. Not to be used in children younger than 6 years.
Contraindications:
- Both vaccines are contraindicated in patients who’ve severe allergic reaction to a previous dose of the vaccine, or who are allergic to any component of the vaccine.
- None of the vaccines is recommended for use in children younger than 2 years.
- Ty21a vaccine should be avoided in pregnancy and immunocompromised individuals as it is a live-attenuated vaccine. Vi capsular vaccine may be used in pregnant women only if clearly indicated.
Precautions:
- Antimicrobial drugs may interfere with the activity of Ty21a vaccine. Therefore it should not be given until at least 3 days after the last antibiotic dose.
- Vaccination preferably should be delayed in a person with acute febrile illness or acute gastroenteritis.
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