Prevention

Prevention of enteric fever includes:

• reducing the risk of contamination of food and drink by ensuring a safe water supply and improved sanitation. Unfortunately for travellers, few maintain good standards of hygiene
• immunisation to S. typhi may be performed on a mass scale though this may be overcome by a large inoculum of S.typhi. Also, a vaccine for S. paratyphi is not available (1,2)
• immunisation is recommended for travellers to most countries in the developing world and for laboratory workers handling specimens from suspected cases (1)
• Vi polysaccharide vaccine and Ty21a vaccine are available for use in travellers. The typhoid Vi conjugate vaccine is now recommended by the WHO
  in endemic areas (2)
  • Ty21a is a live attenuated oral vaccine. Fever was more common following Ty21a vaccination compared with placebo
  • Vi capsular polysacchride vaccine (ViPS) is given as a single injection
  • re-vaccination is recommended after three years with both these vaccines
  • both these vaccines are of limited value in preschool children because of difficulties of administration (Ty21a oral capsules) or inferior immune response (ViPS)

Repeated exposure to infection gives adults a greater degree of natural immunity.

Reference:

1. GP magazine (September 24th 2004): 44.
2. Basnyat B et al. Enteric Fever. BMJ 2021;372:n437 http://dx.doi.org/10.1136/bmj.n437