A Study to Evaluate the Safety, Tolerability, and Immunogenicity of MVC-COV1901 or MVC-COV1901(Beta) Against COVID-19

The purpose of this study is to assess the safety, tolerability, and immunogenicity of a booster dose of vaccine in participants who are generally healthy or with stable pre-existing health conditions. Study details include: * The study duration per participant will be approximately 209 days (28 days screening, 1 day vaccination, and 180 days follow-up). * The treatment duration will be 1 day. -The visit frequency will be 6 on-site visits (1 screening visit, 1 treatment visit, and 4 follow- up visits) and 1 phone visit.