• Participants who meet all the following criteria at Screening are eligible to participate in the study:

• Must be a male or female aged 18 - 64 (inclusive) at the time of enrolment

• Must have completed at least a primary course of 2 doses of any approved COVID-19 vaccine which the last dose have to be mRNA vaccine and completed the last doser 3 months or more

• Must be able to communicate effectively with study personnel and considered reliable, willing, and cooperative in terms of compliance with the protocol requirements

• Participants must sign the written informed consent form prior to undertaking any protocol-related procedures

• SARS-CoV-2 rapid antigen test is negative at Day 1 (the day of receiving the study booster dose)

• Does not intend to receive any other authorized/approved COVID-19 vaccine at the time of enrolment and up to 3 months of the study

• Males must be surgically sterile (\>30 days since vasectomy with no viable sperm), practice true abstinence or, if engaged in sexual relations with a female of child-bearing potential, the participants and their partner must use an acceptable, highly effective, double-barrier contraceptive method\* from Screening and for a period of at least 60 days after vaccination

• A female participant is eligible if she is not pregnant, or breastfeeding indicated by one of the following conditions:

∙ With childbearing potential (WOCBP): she agrees to use an effective contraceptive method or abstinence from at least 4 weeks prior to the study intervention administration until at least 12 weeks after the study intervention administration, or

‣ With non-childbearing potential. To be considered of non-childbearing potential, a female must be post-menopausal for at least 1 year or surgically sterile

• Participants must be in general good health\* based on medical history and physical examination, as determined by the PI at Screening.

⁃ Participants must agree to refrain from donating blood, plasma, ova, sperm, or organs during the whole study.