Safety Outcomes:

• Primary Safety Outcomes: participants recorded any injection site-specific adverse reactions and systemic adverse reactions for 7 days after injection.
• Secondary Safety Outcomes: participants recorded any unsolicited symptoms during the 28-day follow up period to the initial injection.
• Laboratory Safety Tests: performed before and 4 days after each injection to check for any toxic effects from the vaccination, included blood work, liver enzymes, bilirubin, and urine proteins. Considered Secondary Safety Outcomes.

Primary Humoral Immunogenicity Outcomes:

• Neutralizing antibody titers and specific IgG-binding antibody titers
• Phase I: blood samples collected before immunization, at days 4 and 14 after each injection, and 21 days after the first dose.
• Phase II: blood samples collected before immunization from all of the participants, and at day 14 in randomly selected half of the participants for the immunogenicity subset.
• PRNT was used to find the neutralization capacity against live SARS-CoV-2 and the values were used to determine the serum dilution that will still produce a 50% decrease in SARS-CoV-2 plaque formation.
• An enzyme-linked immunosorbent assay kit using the whole inactivated virus as the coating agent was used to measure the total specific IgG antibody responses.
• Seroconversion rate was defined and used to determine the threshold for the different antibody titers.