What are the recommendations for typhoid (Salmonella Typhi) fever vaccination?

Typhoid Vaccine Recommendations

For travelers to endemic areas, laboratory workers, and household contacts of typhoid carriers, the typhoid conjugate vaccine (TCV) should be the first-choice vaccine due to its superior 78% four-year efficacy, effectiveness in young children, and less frequent boosting requirements. 1

Who Should Receive Typhoid Vaccination

The CDC identifies three primary groups requiring vaccination:

• Travelers to endemic regions: Particularly those visiting developing countries in Latin America, Asia, and Africa with prolonged exposure to potentially contaminated food and water 1
• Laboratory workers: Those who frequently handle S. typhi in microbiology settings 1
• Household contacts: Persons with intimate, continued exposure to documented typhoid carriers 1

Vaccine Selection Algorithm

First-Line Choice: Typhoid Conjugate Vaccine (TCV)

TCV (Typbar-TCV) is the preferred option for all ages due to superior long-term protection and reduced boosting frequency. 1 This vaccine demonstrates:

• 78% efficacy over four years 1
• Effectiveness in infants and young children 1
• Excellent safety profile with mild, self-limited adverse events 1

Alternative Options When TCV Unavailable

Vi Polysaccharide Vaccine (Injectable)

• Single 0.5 mL dose for adults and children ≥10 years 1
• 0.25 mL subcutaneously for children 6 months to <10 years (two doses separated by ≥4 weeks) 1
• First-year efficacy: 69% 2
• Three-year cumulative efficacy: approximately 55% 1, 2
• Requires boosters every 2-3 years with continued exposure 1, 3
• Common adverse effects: injection site pain and swelling, but rarely systemic effects 1

Oral Ty21a Vaccine (Vivotif)

• Four enteric-coated capsules taken on alternate days for adults and children ≥10 years 1
• Each capsule taken with cool liquid no warmer than 37°C, approximately 1 hour before meals 1
• Reduces infection by approximately 67% for at least 4 years 1
• Three-year cumulative efficacy: 50% 1, 2
• Requires complete four-dose series revaccination every 5 years 1, 3
• Adverse event rates comparable to placebo (<1/100,000 doses) 1

Critical Contraindications and Precautions

Oral Ty21a Vaccine Contraindications:

• Children <6 years of age 1
• Immunocompromised persons, including those with asymptomatic HIV infection 1
• Must wait at least 72 hours after completing antibiotics before administration 4

Vi Polysaccharide Vaccine Contraindications:

• History of severe local or systemic reaction after previous dose 1
• Should not be used in immunocompromised patients or those with HIV due to inadequate immune response 1

Timing Considerations

Pre-Travel Vaccination:

• Administer vaccines with sufficient time before departure to allow immune response development 1

Post-Infection Vaccination:

• Patients recovered from typhoid fever do not require vaccination, but if desired, wait at least 2-4 weeks after clinical recovery 4
• Parenteral Vi polysaccharide vaccine is preferred post-infection as it poses no theoretical risk 4

Essential Caveats

No vaccine provides 100% protection (efficacy range 50-80%), and protection can be overwhelmed by large bacterial inocula. 1, 3 Therefore:

• Vaccination does NOT substitute for careful food and water selection 1, 3, 4
• Hand hygiene and avoiding high-risk foods/beverages remain essential 1
• Travelers must maintain biosafety precautions regardless of vaccination status 5

Real-World Effectiveness

In US travelers to Southern Asia from 2008-2011, typhoid vaccination demonstrated 80% effectiveness (95% CI: 66-89%), strongly supporting current vaccination recommendations. 6