The Pfizer-BioNTech vaccine, officially known as BNT162b2, is an mRNA vaccine developed to protect against COVID-19. It works by using a small piece of the virus's genetic material to instruct cells to produce a harmless spike protein, prompting the immune system to recognize and fight the virus if exposed in the future. This vaccine was one of the first to receive emergency use authorization from health authorities, including the U.S. Food and Drug Administration (FDA). Clinical trials demonstrated its effectiveness in reducing the risk of severe illness, hospitalization, and death caused by the SARS-CoV-2 virus.