What are the two main typhoid fever vaccines and who should receive them?

• A. Oral Ty21a live attenuated vaccine and injectable Vi capsular polysaccharide vaccine; travelers to high-risk areas and some lab workers
• B. Inactivated whole-cell vaccine; travelers to high-risk areas
• C. Live attenuated influenza vaccine; general population
• D. BCG vaccine; healthcare workers

Answer: (A)

Two vaccines protect against typhoid fever: an oral live attenuated vaccine (Ty21a) and an injectable Vi capsular polysaccharide vaccine. The oral vaccine comes as a four-dose series taken on alternate days; protection builds after completing the series and lasts for several years (roughly five years with boosters). The injectable Vi vaccine is a single shot that provides protection for a couple of years and is convenient for those who prefer not to take an oral series or who need rapid protection. These options are especially recommended for travelers to typhoid-endemic areas and for certain laboratory workers who may be exposed to Salmonella typhi. Other listed vaccines are for different diseases and not used for typhoid fever.