In the United States, an emergency use authorization (EUA) is "a mechanism to facilitate the availability and use of medical countermeasures, including vaccines, during public health emergencies, such as the current COVID19 pandemic", according to the Food and Drug Administration (FDA). Pfizer applied for an EUA on 20 November 2020, and the FDA approved the application three weeks later on 11 December 2020. The US Centers for Disease Control and Prevention (CDC) Advisory Committee on Immunization Practices (ACIP) approved recommendations for vaccination of those aged sixteen years or older. Following the EUA issuance, BioNTech and Pfizer continued the PhaseIII clinical trial to finalize safety and efficacy data, leading to application for licensure (approval) of the vaccine in the United States. On 10 May 2021, the US FDA also authorized the vaccine for people aged 12 to 15 under an expanded EUA. The FDA recommendation was endorsed by the ACIP and adopted by the CDC on 12 May 2021. In October 2021, the EUA was expanded to include children aged 5 through 11 years of age. In June 2022, the EUA was expanded to include children aged six months through four years of age.
