Typhoid vaccination

Different vaccines:

• whole cell typhoid vaccine - no longer available
• polysaccharide typhoid vaccine - Typhim Vi antigen
  • non-conjugated polysaccharide vaccines are poorly immunogenic in infants and young children
  • little definitive data on the efficacy of Vi vaccine in children aged less than 18 months -in 2008, the lower age limit for Typhim Vi was increased from 18 months to two years- ineffective in children less than 18 months
  • an inactive vaccine
    
    
• oral typhoid vaccine (Ty21a)
  • oral typhoid vaccine contains a live, attenuated strain of S. typhi (Ty21a) in an enteric-coated capsule
  • a three-dose regimen gives a cumulative three-year efficacy of about 50 to 60%
  • vaccine is indicated for persons from six years of age
    
    
• whole-cell typhoid vaccine
  • injectable, killed, whole-cell typhoid vaccine contains heat-inactivated, phenol-preserved S. typhi organisms
  • this vaccine is highly reactogenic and is no longer used in the UK

Typhoid vaccine is indicated for active immunisation against typhoid fever and is recommended for:

• travellers visiting typhoid-endemic areas whose planned activities put them at higher risk
• travellers to endemic areas with frequent and/or prolonged exposure to conditions where sanitation and food hygiene are likely to be poor
• laboratory personnel who may handle S. typhi in the course of their work

Check uptodate details in the The Green Book before prescribing/administering a vaccination.

Check the Summary of Product Characteristics (SPC) prescribing/administering a vaccine.

Notes:

• immunisation can be overcome by a large inoculum of S.typhi (1) - protection by vaccination may be less if a large number of infective organisms are ingested (2)
• Vi vaccines are routinely given intramuscularly into the upper arm or anterolateral thigh. Intradermal injection may cause a severe local reaction and should be avoided. Vaccines should be given by deep subcutaneous injection to individuals with a bleeding disorder. Vaccines must not be given intravenously. Ty21a vaccine capsules are taken orally
• a South African study found the cumulative three-year efficacy of Vi polysaccharide vaccine against culture-positive typhoid to be 55% in children aged six to 15 years
• a three-dose regimen of Ty21a oral vaccine gives a cumulative three-year efficacy of about 50 to 60%
• Primary immunisation
  • the immunisation schedule of Vi vaccine consists of a single dose; for Ty21a vaccine, a three-dose course

Reference:

1. GP magazine (September 24th 2004): 44.
2. The Green Book. Chapter 33 - Typhoid (April 2019)