Is a typhoid vaccine necessary for travel to certain parts of Asia, Africa, or Latin America?

Typhoid Vaccine for Travel to [LOCATION]

Direct Recommendation

Yes, typhoid vaccination is necessary if you are traveling to parts of Asia, Africa, or Latin America where there is recognized risk of exposure to typhoid fever, particularly if you will have prolonged exposure to potentially contaminated food and water. 1, 2

Who Should Receive Typhoid Vaccination

The CDC specifically recommends typhoid vaccination for travelers to developing countries in Latin America, Asia, and Africa who will have prolonged exposure to potentially contaminated food and drink. 1

Additional indications include:

• Persons with intimate exposure to a documented typhoid carrier (such as continued household contact) 1, 2
• Microbiology laboratory workers who frequently work with S. typhi 1, 2

Geographic Risk Assessment

The highest risk areas include:

• South Asia (particularly India, Pakistan) - where 35.4% of typhoid cases in travelers are acquired 3
• Southeast Asia and Indonesia - accounting for 32.2% of traveler typhoid cases 3
• Parts of Africa (such as South Africa) 4
• Central and South America (such as Peru, Bolivia, Costa Rica) - though lower risk than Asia (only 6.4% of cases) 4, 3

Travelers to the Indian subcontinent face the greatest risk and should be prioritized for vaccination. 3

Vaccine Options and Efficacy

First-Line Choice: Vi-TT Conjugate Vaccine (Typbar-TCV)

The WHO recommends Vi-TT conjugate vaccine as the preferred option due to superior efficacy of 78% over four years, less frequent boosting requirements, and effectiveness in young children. 1

Alternative Options When TCV Unavailable:

Vi Polysaccharide Vaccine (Injectable):

• Prevents approximately 69% of typhoid cases in year 1 (high-certainty evidence), 59% in year 2 (moderate-certainty evidence), and cumulative 55% efficacy over 3 years 5
• Single 0.5 mL dose intramuscularly or subcutaneously for adults and children ≥10 years 1
• Requires boosters every 2-3 years with continued exposure 1, 2
• Must be given at least 2 weeks before travel 2

Ty21a Oral Vaccine (Vivotif):

• Prevents approximately 50% of typhoid cases over 2.5-3 years (moderate-certainty evidence) 5
• Four enteric-coated capsules taken on alternate days with cool liquid no warmer than 37°C, approximately 1 hour before meals 1, 6
• For adults and children ≥6 years (not recommended for children <6 years or immunocompromised persons) 1, 6
• Requires revaccination with full four-dose series every 5 years 1, 6

Critical Timing Considerations

Complete vaccination at least 2 weeks before departure for injectable vaccine, or complete the 7-day oral vaccine series before travel. 2, 6

Essential Caveats

Vaccination is NOT a substitute for careful food and water selection - vaccines are only 50-80% effective and protection can be overwhelmed by large bacterial inocula. 1, 7

Even vaccinated travelers must:

• Avoid potentially contaminated food and water 2, 6
• Practice hand hygiene 1
• Avoid high-risk foods and beverages 1

Common Pitfalls to Avoid

• Do not use Vi polysaccharide vaccine in immunocompromised patients or those with HIV - it produces inadequate immune response in these populations 1
• Do not give oral Ty21a vaccine to immunocompromised persons, including those with asymptomatic HIV infection 1
• Do not assume vaccination provides 100% protection - breakthrough infections occur, especially with high inoculum exposure 1, 7
• Do not forget to plan for booster doses if ongoing exposure continues (every 2 years for Vi polysaccharide, every 5 years for oral Ty21a) 1, 7

Safety Profile

All typhoid vaccines demonstrate excellent safety profiles with mild, self-limited adverse events. 1

• Oral Ty21a: adverse event rates comparable to placebo (<1/100,000 doses), probably does not cause more GI symptoms than placebo 1, 5
• Vi polysaccharide: causes injection site pain and swelling more commonly than placebo, but fever and systemic effects are rare 1, 5