BNT166a

This is a dose-escalation, Phase I/II study evaluating the safety, tolerability, reactogenicity and immunogenicity of the investigational RNA-based multivalent vaccine candidate BNT166a for active immunization against monkeypox (mpox).
This study started with substudy A (SSA) and substudy B (SSB) for which recruitment has been completed. A Substudy C (SSC) was planned, but the sponsor decided not to conduct it. This study will therefore continue with substudy D (SSD).
In SSA and SSB, dosing started with an initial sentinel group, followed by the expansion cohort.
This study was initially planned to investigate two vaccine candidates (the quadrivalent BNT166a and the trivalent BNT166c). The sponsor decided to not activate the groups with BNT166c.