Protective Activity of Vi Capsular Polysaccharide Vaccine Against Typhoid Fever

Lancet. 1987 Nov 21;2(8569):1165-9. doi: 10.1016/s0140-6736(87)91316-x.

Abstract

The protective efficacy against typhoid fever of a single intramuscular injection of 25 micrograms of the Vi capsular polysaccharide (CPS) was assessed in a randomised double-blind controlled trial. Vaccination of 11,384 children was followed by 21 months' surveillance. 47 blood-culture-proven cases of typhoid occurred in children who received meningococcal A + C CPS vaccine and 19 cases in those vaccinated with Vi CPS. Protective efficacy was 60% calculated from the day of vaccination and 64% from 6 weeks after vaccination. Surveillance also included 11,691 unvaccinated children; 173 cases occurred in this group. Protective efficacy in relation to the unvaccinated group was 77.4% and 81.0% after 21 months, calculated immediately and 6 weeks after vaccination, respectively. Vaccination was associated with minimum local side-effects, and an increase in anti-Vi antibodies occurred, as measured by radioimmunoassay and enzyme-linked immunosorbent assay. Antibody levels remained significantly raised at 6 and 12 months post vaccination. Vi CPS is thus a safe and effective means of typhoid vaccination.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Adolescent
  • Antibodies, Bacterial / analysis
  • Antigens, Bacterial / administration & dosage
  • Antigens, Bacterial / adverse effects
  • Antigens, Bacterial / immunology*
  • Bacterial Vaccines / immunology
  • Child
  • Child, Preschool
  • Clinical Trials as Topic
  • Double-Blind Method
  • Enzyme-Linked Immunosorbent Assay
  • Evaluation Studies as Topic
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Pilot Projects
  • Polysaccharides, Bacterial / immunology
  • Radioimmunoassay
  • Random Allocation
  • Salmonella typhi / immunology*
  • Typhoid Fever / immunology
  • Typhoid Fever / prevention & control*
  • Typhoid-Paratyphoid Vaccines / administration & dosage
  • Typhoid-Paratyphoid Vaccines / adverse effects
  • Typhoid-Paratyphoid Vaccines / immunology*
  • Vaccination / adverse effects

Substances

  • Antibodies, Bacterial
  • Antigens, Bacterial
  • Bacterial Vaccines
  • Polysaccharides, Bacterial
  • Typhoid-Paratyphoid Vaccines
  • meningococcal group A polysaccharide
  • meningococcal group C polysaccharide