Pfizer–BioNTech COVID-19 vaccine

The Pfizer–BioNTech COVID-19 vaccine, sold under the brand name Comirnaty, is an mRNA-based COVID-19 vaccine developed by the German biotechnology company BioNTech. For its development, BioNTech collaborated with the American company Pfizer to carry out clinical trials, logistics, and manufacturing. It is authorized for use in humans to provide protection against COVID-19, caused by infection with the SARS-CoV-2 virus. 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 had 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 and no serious safety concerns. Most side effects are mild to moderate in severity and are gone within a few days. The most common include mild to moderate pain at the injection site, fatigue, and headaches. Reports of serious side effects, such as allergic reactions, are very rare and no long-term complications have been reported.

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). Distribution and storage are logistical challenges because the vaccine needs to be stored at extremely low temperatures.

In August 2022, a bivalent version of the vaccine (Pfizer-BioNTech COVID-19 Vaccine, Bivalent) was authorized for use as a booster dose in individuals twelve years of age and older in the United States. In September 2022, the BA.1 version of the bivalent vaccine (Comirnaty Original/Omicron BA.1 or tozinameran/riltozinameran) was authorized as a booster for use in the United Kingdom. In September 2022, the European Union authorized both the BA.1 and the BA.4/BA.5 (tozinameran/famtozinameran) booster versions of the bivalent vaccine.