Typhoid Vaccination Guidelines

Introduction to Typhoid Vaccines

The Centers for Disease Control and Prevention (CDC) recommends typhoid vaccination for individuals with continued or repeated exposure to S. typhi, with two main types of vaccines: parenteral inactivated typhoid vaccine (efficacy: 51-76%) and oral live-attenuated Ty21a vaccine (efficacy: 50-80%) 1, 2, 3
The Advisory Committee on Immunization Practices (ACIP) recommends typhoid vaccination for travelers to areas with recognized risk of S. Typhi exposure, persons with intimate exposure to documented typhoid carriers, and laboratory workers who frequently work with S. Typhi 1, 3, 4

The oral live-attenuated Ty21a vaccine is administered as four enteric-coated capsules taken on alternate days, providing approximately 5 years of protection 1, 2
The parenteral inactivated typhoid vaccine is administered as a single 0.5 mL intramuscular injection, providing approximately 2-3 years of protection 1, 2
The efficacy of typhoid vaccines may be overwhelmed by large inocula of S. typhi, and neither vaccine provides 100% protection, so careful food and water selection remains important even after vaccination 1

The CDC recommends revaccination with the entire four-dose series of the oral live-attenuated Ty21a vaccine every 5 years for individuals with continued or repeated exposure to S. typhi 2
The CDC recommends booster doses of the parenteral inactivated typhoid vaccine every 3 years for individuals with continued or repeated exposure 1, 2

Typhoid vaccination is recommended for travelers to areas with recognized risk of S. typhi exposure, particularly those visiting developing countries in Latin America, Asia, and Africa 1, 2
Typhoid vaccination is recommended for persons with intimate exposure to documented typhoid carriers and laboratory workers who frequently work with S. typhi 1, 2
Live-attenuated vaccines, such as the oral typhoid vaccine, are generally contraindicated for individuals with compromised immune systems, such as those on immunosuppressive therapies 1, 2

Serious adverse events are rare, occurring in only 0.47 to 1.3 per 100,000 doses, as reported by the CDC 3
Viable organisms are not shed in the stool of vaccinees who receive the oral live-attenuated vaccine, and secondary transmission does not occur with either vaccine type, as stated by the CDC 1, 3
The injectable typhoid vaccine contains only inactivated (killed) components of the bacteria, posing no risk of shedding or transmission to close contacts, and cannot cause typhoid fever or spread to others 1, 3
There is no need for isolation or special precautions after receiving either vaccine, and the choice between oral and injectable vaccines should be based on contraindications, convenience, and patient preference rather than concerns about transmission 1, 3