A Study to Learn About COVID-19 RNA-Based Variant-Adapted Vaccine Candidate(s) Against SARS-CoV-2 in Participants Ages 12 Through 64 Years Considered at Higher Risk of Severe COVID-19, and Participants Ages ≥65 Years

The purpose of this study is to learn about the safety, tolerability, and immunogenicity of an updated vaccine against COVID-19. This study is seeking participants 12 through 64 years of age who are considered to be at higher risk for severe COVID-19 disease per study protocol and those 65 years of age and older. All participants in this study will receive 1 shot to their arm of a BNT162b2 (2025/2026 recommended SARS-CoV-2 strain) 30 µg RNA-based vaccine which targets a circulating variant of SARS-CoV-2 and is selected for the 2025-2026 COVID-19 respiratory virus season. This study is about 6 months for each participant. Participants will either be enrolled in Cohort 1 (Groups 1 and 2) or Cohort 2 (Groups 3 and 4). Participants enrolled in Cohort 1 will have at least 4 visits and participants enrolled in Cohort 2 will have at least 3 visits.