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

Typhoid Vaccination Recommendations for India

Typhoid vaccination is strongly recommended for individuals in India who are at high risk of exposure to Salmonella Typhi, including travelers to endemic areas, those with household contact with typhoid carriers, and laboratory workers who frequently handle S. typhi. 1

Target Population for Vaccination

• Vaccination is particularly recommended for travelers within India who will have prolonged exposure to potentially contaminated food and water, especially in areas with poor sanitation 1, 2
• Persons with intimate exposure to documented typhoid fever carriers, such as those with continued household contact 1, 3
• Workers in microbiology laboratories who frequently work with S. typhi 1, 2
• Children should be considered for vaccination, with recommendations suggesting vaccination at age 2 years and a booster at age 5 4

Available Vaccine Types

Two main types of typhoid vaccines are available in India:

• Oral live-attenuated Ty21a vaccine (Vivotif):

  • Reduces laboratory-confirmed infection by approximately 67% for at least 4 years 1
  • Administered as one enteric-coated capsule taken on alternate days to a total of four capsules 1, 3
  • Not recommended for children <6 years of age or immunocompromised persons 1, 3

• Injectable Vi polysaccharide vaccine (Typhim Vi):

  • 51-76% effective in preventing typhoid fever 1
  • Single dose administered intramuscularly 2
  • Approved for use in persons two years of age or older 2

• Newer Vi-TT conjugate vaccine:

  • Recommended by WHO for children aged 6-23 months 5
  • Shows promising efficacy but requires further evaluation 6

Dosage and Administration

Adults and Children ≥10 years:

• Oral Ty21a vaccine: One enteric-coated capsule taken on alternate days to a total of four capsules with cool liquid no warmer than 37°C, approximately 1 hour before meals 7, 1
• Vi polysaccharide vaccine: 0.5 ml subcutaneously or intramuscularly, as a single dose 7, 2

Children 6 months to <10 years:

• Vi polysaccharide vaccine: 0.25 ml subcutaneously for children 6 months to <10 years, given on two occasions separated by ≥4 weeks 7
• Vi-TT conjugate vaccine: Recommended for children aged 6-23 months 5

Booster Recommendations

• Vi polysaccharide vaccine: Reimmunization every 2-3 years under conditions of continued or repeated exposure 1, 2
• Oral Ty21a vaccine: Revaccination with the entire four-dose series every 5 years 1, 3

Important Considerations and Precautions

• Typhoid vaccination is not a substitute for careful selection of food and drink, as vaccines are not 100% effective and protection can be overwhelmed by large inocula of S. typhi 1, 2
• The inactivated typhoid vaccine is contraindicated in individuals with a history of severe local or systemic reaction after a previous dose 1
• The oral typhoid vaccine should not be given to children <6 years of age or immunocompromised persons 1, 3
• Increasing incidence of paratyphoid fever in Asia is concerning as current typhoid vaccines do not provide protection against S. Paratyphi 8
• Emerging antibiotic resistance, particularly to fluoroquinolones, highlights the importance of vaccination as a preventive measure 8, 5

Public Health Implications for India

• India is considered a high-burden country for typhoid fever with significant antimicrobial resistance challenges 5
• The high endemicity of typhoid in India and proven cost-effectiveness of conjugate vaccines support consideration for inclusion in the national immunization program 5
• Morbidity rates in India vary from 102-2219/100,000 population in different parts of the country, with approximately 1% of children up to 17 years suffering from typhoid fever annually in urban slums 4