BioNTech’s BNT162 vaccine candidates are being developed to prevent COVID-19 disease infection. The BNT162 program is evaluating at least 4 experimental vaccines, each of which represents a unique combination of messenger RNA (mRNA) format and target antigen.
Two of the 4 vaccine candidates include a nucleoside modified mRNA (modRNA), one includes uridine containing mRNA (uRNA), and the fourth vaccine candidate utilizes self-amplifying mRNA (saRNA). Each mRNA format is combined with a lipid nanoparticle (LNP) formulation.
BNT162b1 and BNT162b2 are both nucleoside-modified RNAs, formulated in lipid nanoparticles. BNT162b1 encodes an optimized SARS-CoV-2 receptor-binding domain (RBD) antigen, while BNT162b2 encodes an optimized SARS-CoV-2 full-length spike protein antigen.
The larger spike sequence is included in two of the vaccine candidates, and the smaller optimized RBD from the spike protein is included in the other 2 vaccine candidates. The RBD-based candidates contain the piece of the spike that is thought to be most important for eliciting antibodies that can inactivate the virus.