What are the current recommendations for typhoid vaccination (age groups, dosing schedule, preferred typhoid conjugate vaccine brands (Typbar‑TCV (typhoid conjugate vaccine), TyphiBEV (typhoid conjugate vaccine), SKYTyphoid (typhoid conjugate vaccine), ZyVac (typhoid conjugate vaccine)), alternatives (Vi polysaccharide vaccine, live oral Ty21a vaccine), contraindications, and travel advice)?

Typhoid Vaccine Guidelines

Recommended Vaccine Type

Typhoid conjugate vaccine (TCV) is the preferred first-line vaccine for all eligible patients due to superior efficacy (78% at 4 years), longer duration of protection, effectiveness in infants as young as 6 months, and proven efficacy against drug-resistant strains. 1

Available TCV Brands

• Typbar-TCV, TyphiBEV, SKYTyphoid, and ZyVac are all WHO-prequalified typhoid conjugate vaccines that can be used interchangeably 2
• All TCVs use Vi capsular polysaccharide conjugated to protein carriers (typically tetanus toxoid or cross-reacting material) 3

Target Populations for Vaccination

Travelers

• All travelers to endemic areas (Latin America, Asia, Africa, Sub-Saharan Africa, South/Southeast Asia, Western Pacific) with prolonged exposure to potentially contaminated food and water 1
• Complete vaccination at least 1-2 weeks before departure to allow adequate immune response 4

Endemic Population Groups

• Children ≥6 months of age in endemic countries should receive TCV as part of routine immunization 1, 2
• Persons with intimate household contact with documented typhoid carriers 1

Occupational Exposure

• Microbiology laboratory workers who frequently handle S. typhi cultures 5, 1

Dosing Schedules by Vaccine Type

Typhoid Conjugate Vaccine (TCV) - PREFERRED

• Single 0.5 mL intramuscular dose for all ages ≥6 months 1
• Booster: Every 2-3 years for continued occupational exposure 1
• Booster: Consider at 5 years for travelers with repeated exposure, though immunity may wane earlier in children under 2 years 6

Vi Polysaccharide Vaccine - ALTERNATIVE (if TCV unavailable)

• Adults and children ≥10 years: Single 0.5 mL dose subcutaneously or intramuscularly 1
• Children 6 months to <10 years: 0.25 mL subcutaneously, two doses separated by ≥4 weeks 1
• Booster: Every 2 years for continued exposure 1
• Efficacy: 55% at 3 years 1

Oral Live-Attenuated Ty21a Vaccine (Vivotif) - ALTERNATIVE

• Four enteric-coated capsules taken on alternate days (days 1,3,5,7) 4, 1
• Take with cool liquid no warmer than 37°C, approximately 1 hour before meals 1
• Complete series at least 1 week before departure 4
• Booster: Complete 4-dose series every 5 years for continued exposure 4, 7
• Efficacy: 67% protection maintained for at least 7 years 7

Contraindications and Special Populations

TCV and Vi Polysaccharide Vaccine

• Severe reaction to previous vaccine dose 8, 1
• Immunocompromised patients (including HIV) should not receive Vi polysaccharide vaccine due to inadequate immune response 1
• TCV is safe and effective in immunocompromised populations 2

Oral Ty21a Vaccine - MULTIPLE CONTRAINDICATIONS

• Children <6 years of age 4, 1
• All immunocompromised persons, including asymptomatic HIV infection 5, 4, 1
• Concurrent or recent antibiotic use: Wait minimum 72 hours after completing antibiotics before starting vaccine series 8, 4
• Pregnancy (use inactivated alternatives) 5

Post-Infection Vaccination

• Natural immunity after typhoid infection does not require vaccination, but vaccination can be given if desired 8
• Wait at least 2-4 weeks after clinical recovery and completion of antibiotic treatment 8
• Prefer Vi polysaccharide or TCV (inactivated vaccines) post-infection 8
• Avoid oral Ty21a until at least 72 hours after completing antibiotics 8

Critical Caveats and Pitfalls

Vaccine Limitations

• No typhoid vaccine provides 100% protection (efficacy range 50-80%); protection can be overwhelmed by large bacterial inocula 4, 1
• Vaccination does NOT substitute for food and water safety precautions—rigorous hygiene practices remain essential 5, 4, 1
• With Ty21a's 67% efficacy, approximately one-third of vaccinated individuals remain susceptible 4

Emerging Resistance

• TCV has proven effectiveness against extensively drug-resistant (XDR) S. typhi strains, making it particularly valuable in outbreak settings like Pakistan 2, 9
• Field effectiveness of TCV in XDR outbreak: 72% vaccine effectiveness 9

Waning Immunity

• Immunity wanes after 5 years, especially in children under 2 years with TCV 6
• Consider extending primary immunization age or adding booster upon school enrollment in endemic regions 6

Risk Factors to Address

• Consuming meals prepared outside home >1 time per month significantly increases typhoid risk (adjusted OR 3.72) even in vaccinated individuals 9