A Study to Investigate the Safety, Immunogenicity of Bivalent mRNA Vaccine RQ3027 and RQ3025 as a Booster Dose in Healthy Adults

Inclusion Criteria: * Healthy participants who are determined by medical history, physical examination, and clinical judgment of the investigator to be eligible for inclusion in the study. * Participants 18 through 55 years of ages. * Participants who have received at least 3 doses COVID-19 vaccine. * Participants with the last prior dose being 90 or more days before Visit 1(Day 0) or recovered from COVID-19 at least 28 days. * Participants able to comply with all scheduled visits, laboratory tests and investigator's instruction. Exclusion Criteria: * Women who are pregnant or breastfeeding. * Enrolling in or planning to participate other interventional clinical study. * Has received systemic immunoglobulins or blood products within 3 months prior to the day of screening. * History of anaphylaxis, urticaria, or other significant adverse reaction requiring medical intervention after receipt of a vaccine. * Bleeding disorder considered a contraindication to intramuscular injection or phlebotomy. * Continued using anticoagulants such as coumarin and related anticoagulants (i.e., warfarin) or oral anticoagulants (i.e., apixaban, rivaroxaban, dabigatran, and edoxaban). * Having coronary heart disease, hypertension, diabetes, chronic respiratory diseases, tumors and poorly controlled. * Immunocompromised or having immunosuppressive therapy. * Suspected or confirmed alcohol/drug dependence. * Investigator decide unsuitable factors for participating in clinical trials in the investigator's judgment