This Phase 3 study will evaluate the efficacy of a Typhoid conjugate vaccine (Vi-TCV) in Malawi, Africa among children age 9 months through 12 years. Participants will be randomized in a 1:1 ration to receive the study vaccine or the control vaccine (meningococcal group A conjugate vaccine - MCV-A).
On September 16, 2021 The New England Journal of Medicine published the results of this clinical trial.
RESULTS: The intention-to-treat analysis included 28,130 children, of whom 14,069 were assigned to receive Vi-TCV and 14,061 were assigned to receive the MenA vaccine. Blood culture–confirmed typhoid fever occurred in 12 children in the Vi-TCV group (46.9 cases per 100,000 person-years) and in 62 children in the MenA group (243.2 cases per 100,000 person-years). Overall, the efficacy of Vi-TCV was 80.7% (95% confidence interval [CI], 64.2 to 89.6) in the intention-to-treat analysis and 83.7% (95% CI, 68.1 to 91.6) in the per-protocol analysis. In total, 130 serious adverse events occurred in the first 6 months after vaccination (52 in the Vi-TCV group and 78 in the MenA group), including 6 deaths (all in the MenA group). No serious adverse events were considered by the investigators to be related to vaccination.
CONCLUSIONS: Among Malawian children 9 months to 12 years of age, administration of Vi-TCV resulted in a lower incidence of blood culture–confirmed typhoid fever than the MenA vaccine.