The Pfizer–BioNTech COVID-19 vaccine (INN: tozinameran), sold under the brand name Comirnaty, is an mRNA-based COVID-19 vaccine developed by the German biotechnology company BioNTech. It is authorized for use in people aged twelve years and older in some jurisdictions and for people sixteen years and older in other jurisdictions, to provide protection against COVID-19, caused by infection with the SARS-CoV-2 virus. For its development BioNTech collaborated with Pfizer, an American company, for support with clinical trials, logistics, and manufacturing. The vaccine is given by intramuscular injection. It is composed of nucleoside-modified mRNA (modRNA) encoding a mutated form of the full-length spike protein of SARS-CoV-2, which is encapsulated in lipid nanoparticles. Initial advice indicated that vaccination required two doses given 21 days apart, but the interval was later extended to up to 42 days in the US, and up to four months in Canada.

Clinical trials began in April 2020; by November 2020, the vaccine entered Phase III clinical trials, with over 40,000 people participating. An interim analysis of study data showed a potential efficacy of 91.3% in preventing symptomatic infection within seven days of a second dose. The most common side effects include mild to moderate pain at the injection site, fatigue, and headaches. Reports of serious side effects, such as allergic reactions, are very rare; no long-term complications have been reported. Monitoring of the primary outcomes from the trials will continue until August 2021, while monitoring of the secondary outcomes will continue until May 2023. As part of the updates for the Phase III clinical trials posted in June 2021, the assessment of biostability will be studied to further describe the potential protection given by the vaccine against emerging SARS-CoV-2 Variants of Concern.

The vaccine is the first COVID‑19 vaccine to be authorized by a stringent regulatory authority for emergency use and the first cleared for regular use. In December 2020, the United Kingdom was the first country to authorize its use on an emergency basis. It is authorized for use at some level in the majority of countries. On 23 August 2021, the Pfizer–BioNTech vaccine became the first COVID-19 vaccine to be approved in the United States by the Food and Drug Administration (FDA) for those aged sixteen years and older.

As of 30 March 2021, Pfizer and BioNTech aimed to manufacture about 2.5 billion doses in 2021. Distribution and storage is a logistical challenge because the vaccine needs to be stored at extremely low temperatures. BioNTech and Pfizer are testing a freeze-dried version that would not need ultracold storage.