• Adults 18 years of age and above, at time of screening.

• Completed primary approved/authorized COVID-19 vaccination series with ≥ 2 mRNA vaccine doses.

• Last COVID-19 vaccine received ≥6 months prior to study vaccination.

• Male and female participants of childbearing potential must agree to consistently use a highly effective method of contraception from at least 30 days prior to enrollment and through 3 months after the study vaccination.

• Male participants must refrain from sperm donation from the day of study vaccination through the end of the study. Female participants must refrain from egg donation at least 30 days prior to study vaccination through the end of the study.

• Is medically stable, as determined by the site investigator (based on review of health status, vital signs, medical history, and physical examination) with screening lab values within normal limits or abnormalities assessed as not clinically significant. Screening platelet count must be \>140,000/μL.

• Agree to not participate in any other SARS-CoV-2 infection prevention trial (vaccine, drug, biologic, PrEP) during participation in the study.

• Willing and able to provide informed consent prior to initiation of study procedures.

• Available for all study visits, willing to participate in all study procedures, and not planning to relocate from the area for the duration of the study.

⁃ Negative rapid molecular Covid test at the screening visit and on Day 1 prior to vaccine dosing.