Typhoid Fever Vaccines

Vaccine Available as an Oral Series or a Single-Dose Injection

Typhoid fever immunization is recommended for all travelers to less-developed countries, especially those in Central and South America, Africa, Southeast Asia, and the Indian subcontinent. The highest risk countries are Peru, India, Pakistan, and Chile. However, about half of all cases of typhoid fever reported in American tourists are acquired from travel to Mexico even though the risk of disease is lower there. Typhoid fever is typically spread person-to-person by food handlers who do not wash their hands adequately after bowel movements. Visitors who stray off the beaten path and eat meals prepared at foodstands or by street vendors are at highest risk. Carefully selecting restaurants with close attention to their sanitation standards can reduce the risk.

There is now an oral typhoid vaccine and a single-dose injectable vaccine that produces fewer side effects than the older two-dose injectable vaccine. Both vaccines are equally effective and offer 65% to 75% protection against the disease.

The oral vaccine (Vivotif) contains a live but weakened strain of the Salmonella bacteria that causes typhoid fever. The vaccine consists of four capsules that are taken every other day over a one-week period. The capsule protects the vaccine against stomach acid so it remains active when it reaches the intestine where the immunity develops. The oral vaccine can be given either as a first-time dose or as a booster dose. The protection should last about 5 years, at which time another booster dose would be needed if traveling again. The oral vaccine is not recommended for children under 6 years old. The oral typhoid vaccine is available at pharmacies by prescription only and has a retail price of around $35.

The single-dose injectable vaccine (Typhim Vi) containing capsular polysaccharide antigen became available in February, 1995. The protection offerred by this vaccine is effective starting 2 weeks after injection and should last for 2 years. Subsequent booster doses are recommended at 2-year intervals. This vaccine can be used in children as young as 2 years old. Side effects, while greater than those of the oral vaccine, are much less than those experienced with the old 2-dose injectable vaccine.

Those travelers at risk for typhoid fever should also worry about possible exposure to hepatitis A which is acquired in a similar manner. Therefore, hepatitis A vaccine is also recommended prior to travel.

Gary P. Barnas, MD
Associate Professor
General Internal Medicine

Each year, Medical College of Wisconsin physicians care for more than 180,000 patients, representing nearly 500,000 patient visits. Medical College physicians practice at Children's Hospital of Wisconsin, Froedtert Memorial Lutheran Hospital, the Milwaukee VA Medical Center, and many other hospitals and clinics in Milwaukee and southeastern Wisconsin.