BNT162b2 is a COVID-19 vaccine developed by Pfizer and BioNTech. It uses messenger RNA (mRNA) technology to instruct cells in the body to produce a harmless piece of the virus's spike protein. This process helps the immune system recognize and fight the actual virus if exposed in the future. The vaccine has been shown to be effective in preventing COVID-19 and is administered in two doses, typically three weeks apart. Clinical trials demonstrated its safety and efficacy, leading to emergency use authorization in many countries around the world.