Evaluation of a new Vi polysaccharide typhoid vaccine in children aged 2-5 years.

Typhoid fever is a major cause of morbidity and mortality in many parts of the world. In view of the increasing resistance of Salmonella typhi against antibiotics and the high costs associated with improving sanitation conditions, vaccination programs would be of great benefit. We report on the evaluation of a new candidate VI (sic) polysaccharide typhoid vaccine (TypheriX (sic), SmithKline Beecham Pharmaceuticals), tested in Filipino children aged 2-5 years where the profile was compared with that of a competitor-vaccine (Typhim (sic), Pasteur Merieux Connaught). Vaccination with the new candidate vaccine was followed by fewer general symptoms (2.9%) than with the competitor vaccine (14.1%), particularly with lower incidence of fever. The new candidate vaccine is also highly immunogenic: >99% of the vacinees were immune 28 days post vaccination with comparable GMTs of 3597 EL.U/ml for TypheriX (sic) and 3365 EL.U/ml for Typhim (sic). This trial shows that the available VI (sic) polysaccharide vaccines provide a reliable means in preventing a disease responsible for a significant morbidity and placing a heavy burden on health budgets.