The BNT162b2 vaccine is an mRNA-based COVID-19 vaccine that encodes the spike protein antigen of SARS-CoV-2. It has shown about 95% efficacy in preventing COVID-19 after two doses and provides significant protection against various strains, including Alpha, Beta, Delta, and Omicron. Safety data from clinical trials and real-world studies indicate that the BNT162b2 vaccine is generally well-tolerated.