A Phase 4 Open-label, Single-arm Study to Evaluate the Safety and Immunogenicity of an Omicron Subvariant-based SARS-CoV-2 Recombinant Spike (rS) Vaccine Adjuvanted With Matrix-M in Participants ≥ 65 Years of Age and Participants 12 Through 64 Years of Age Who Are at Increased Risk for Severe COVID-19 Illness | Arctuva