소아 및 성인에서의 COVID-19 백신 연구

The purpose of this study is to learn about the safety and effects of updated COVID-19 vaccines (called BNT162b2) in participants 5 Through 64 Years of Age with risk factors for Severe COVID-19, and Participants 65 Years of Age and Older. This study is seeking participants who: * are medically stable * have not had a recent COVID-19 infection or a recent COVID-19 vaccination * have not received certain routine vaccines recently * participants that are 5 through 64 years of age will need to have at least 1 medical condition that increase their risk of complications from COVID-19. Participants in Cohort 1 of this study will receive 1 injection into their arm of BNT162b2 vaccine 1 which targets COVID-19. The study team and participants will know which injection they receive. Participants in Cohort 2 of this study will randomly receive 1 injection into their arm of either: BNT162b2 vaccine 1; BNT162b2 vaccine 2, or BNT162b2 vaccine 3 which targets COVID-19. The study team and participants will not know which injection they receive. Participants will be in the study for about 6 months and will have at least 3 study visits. Participants will record side effects and complete diaries following visit procedures. For Cohort 1 the study team will collect a nose swab and blood samples at 2 of the 3 visits. For Cohort 2 the study team will collect a nose swab and blood samples at all of the visits.