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