Durable Efficacy of Single-Dose Typhoid Conjugate Vaccine Among Children in Malawi

In children aged 9 months to 12 years, one dose of typhoid conjugate vaccine protected against blood-culture confirmed typhoid fever for ≥4 years.

Trials in Asia and Africa (e.g., NEJM JW Infect Dis Aug 25 2021 and Lancet 2021 Aug 21; 398:675 [e-pub]) have confirmed the safety and efficacy of typhoid conjugate vaccines in children. But how long does this protection last? Investigators conducted a phase 3, double-blind trial in Malawi. Healthy children (age range, 9 months–12 years) were randomly assigned to one dose of Vi polysaccharide conjugated to tetanus toxoid (Vi-TT) or meningococcal group A conjugate (MenA) vaccine. In all, >28,000 children (median age, 6 years) participated in 2018 and were followed through September 2022 (median follow-up, 4.3 years).

Blood-culture confirmed typhoid fever was diagnosed in 24 vs. 110 children (Vi-TT vs. MenA) for a cumulative Vi-TT efficacy of …

Reviewing Author

Mary E. Wilson, MD

Disclosures

Consultant/Advisory BoardOneHealthTrust (formerly Center for Disease Dynamics, Economics, and Policy); Global Health Institute, University of Wisconsin

RoyaltiesUpToDate

Editorial BoardsJournal of Travel Medicine

Mary E. Wilson, MD

Disclosures

Consultant/Advisory BoardOneHealthTrust (formerly Center for Disease Dynamics, Economics, and Policy); Global Health Institute, University of Wisconsin

RoyaltiesUpToDate

Editorial BoardsJournal of Travel Medicine

Durable Efficacy of Single-Dose Typhoid Conjugate Vaccine Among Children in Malawi

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Reviewing Author