Safety and immunogenicity of a plant-produced Pfs25 virus-like particle as a transmission blocking vaccine against malaria: A Phase 1 dose-escalation study in healthy adults.

•Report of a Phase I clinical trial to assess a malaria transmission blocking vaccine.•P. falciparum Pfs25 virus-like particle produced under cGMP in a plant-based system.•The vaccine candidate displays an acceptable safety and tolerability profile.•The vaccine candidate induced Pfs25-specific IgG in a dose dependent manner.•However, low transmission reducing activity implies need for an improved formulation.