The BNT162 vaccine program is being developed by Germany-based BioNTech SE (BNTX) and Pfizer Inc. (PFE).Current Status: BNT162 is under a phase I/II clinical trial in Europe and the U.S. Preliminary trial data reported on July 1 were promising. Mode of Action:The BNT162 program consists of four mRNA-based vaccine candidates, representing different mRNA formats and targeting different antigens.Two of the vaccine candidates contain nucleoside modified mRNA (modRNA), one has uridine containing mRNA (uRNA) and the fourth contains self-amplifying mRNA (saRNA). While 2 candidates contain a larger sequence of the SARS-CoV-2 spike protein, the other two candidates contain the smaller optimized receptor-binding domain (RBD) from the spike protein.Upon vaccination, the mRNA uptake into cells results in vaccine antigen synthesis. This stimulates the immune system of the vaccinated individual, generating an immune response to the vaccine antigen and prevents subsequent infection upon exposure to the virus.Next Milestone:A phase IIb/III safety and efficacy study is expected to begin as early as July 2020.