How effective is typhoid vaccine, and who should get it?
There are three different typhoid vaccines: one is given by mouth (Ty21a) and two are injected (the ViCPS, or “Vi” form, and a parenteral inactivated, older form). Each protects roughly 50 to 80 percent of recipients. The schedule depends on the age of the recipient and on the form used. The vaccine given by mouth requires careful adherence to a somewhat complex eight-day regimen. The “Vi” form requires one injection initially. The other injected form initially requires two doses separated by at least four weeks. No country currently requires typhoid fever vaccine for entry. However, because there is a risk of typhoid fever for U.S. travelers, the vaccine is recommended for those who will have prolonged exposure to potentially contaminated food and drink while visiting the Indian subcontinent, or developing countries in Latin America, Asia, or Africa. Vaccination is of particular value for persons who will be visiting smaller cities, villages, and rural areas. Vaccination should not be
