COVID-19 Vaccines

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 a single age-appropriate dose (30 mcg for participants aged ≥12 years; 10 mcg for participants aged 5-11 years) of BNT162b2 vaccine 1 which targets COVID-19 (2026/2027 recommended strain) injected in the upper arm. 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 upper 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.

The purpose of this study is to learn about the safety and effects of an updated COVID-19 vaccine (called BNT162b2) in adults 18 to 64 years of age. This study is seeking participants who: * are medically stable * have not had a recent COVID-19 infection * have not had a recent vaccination * do not have medical conditions that increase their risk of complications from COVID-19 All participants in this study will randomly receive 1 injection into their arm of either: * BNT162b2 vaccine which targets COVID-19 and is selected for the 2026-2027 COVID-19 season, or * Tdap vaccine which targets tetanus, diphtheria, and pertussis (whooping cough). The study team and participants will not know which injection they receive. We will evaluate safety and SARS-CoV-2 spike protein levels in people receiving each of these vaccines. Participants will be in the study for about 12 months.