Safety, Reactogenicity, and Immunogenicity of an Mpox mRNA Vaccine Candidate, BNT166a, in Healthy Adults Aged 18 to 64 Years in Africa: A Randomized, Double-blind, Placebo-controlled Phase II Trial

What this Trial Is About

Researchers are conducting a randomized, double-blind, placebo-controlled Phase II trial to study the safety, reactogenicity, and immune response of an mRNA-based Mpox vaccine candidate called BNT166a in healthy adults. The study includes two groups: one with adults aged 18 to 45 who have never had Orthopoxvirus infection or vaccination, and another with adults aged 18 to 64 who have prior Orthopoxvirus experience. This trial is sponsored by BioNTech SE and aims to assess reactions after one and two vaccine doses. Participants will receive two doses of either BNT166a or a placebo injection into the deltoid muscle of the same non-dominant arm, spaced at least 28 days apart. The study duration for each participant is approximately 14 months. The trial evaluates various dose levels in both Orthopoxvirus-naive and experienced cohorts, with careful monitoring throughout the study. During the study, participants will be monitored for local and systemic reactions up to 7 days after each dose, along with any use of medications to reduce symptoms. Researchers will track any adverse events, including serious or medically attended events, for up to 14 months. Immune responses will be measured at baseline and one month after each dose by testing antibody levels against specific Mpox and related virus proteins. Participants will have regular assessments and safety monitoring during the entire study period.

A Randomized Clinical Trial Investigating the Safety, Reactogenicity, and Immunogenicity After Immunization With an mRNA-based Mpox Vaccine Candidate in Africa