Solicited local ARs included injection site erythema, injection site pain, injection site induration/swelling, and injection site tenderness. A summary of serious and all other non-serious adverse events regardless of causality is located in the Reported Adverse Events module.

Solicited systemic ARs included arthralgia, chills, diarrhea, dizziness, fatigue, fever (categorized by measured body temperature), headache, myalgia, and nausea/vomiting. A summary of serious and all other non-serious adverse events regardless of causality is located in the Reported Adverse Events module.

Unsolicited AEs were defined as any spontaneously reported or discovered AE. A summary of serious and all other non-serious adverse events regardless of causality is located in the Reported Adverse Events module.

An MAAE was defined as an AE that led to an unscheduled visit (including a telemedicine visit) with a healthcare provider (\[HCP\], e.g., nurse, nurse practitioner, physician's assistant, physician). An SAE was defined as any event that resulted in death, was immediately life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity or was a congenital anomaly/birth defect arising from a pregnancy conceived after receipt of study vaccine. A summary of serious and all other non-serious adverse events regardless of causality is located in the Reported Adverse Events module.

Data are presented for the number of participants with a NAb seroconversion response as determined by the surrogate virus neutralization test (sVNT). Seroconversion was defined as a ≥4-fold increase in antibody concentration from baseline.

COVID-19 was defined as a positive SARS-CoV-2 test and at least one of the following that was a new or worsening finding: ⦁ Fever or chills ⦁ Cough ⦁ Shortness of breath or difficulty breathing ⦁ Fatigue ⦁ Muscle or body aches ⦁ Headache ⦁ New loss of taste or smell ⦁ Sore throat ⦁ Congestion or runny nose ⦁ Nausea or vomiting ⦁ Diarrhea Data are presented for the number of participants with a first occurrence of COVID-19 with no evidence of prior infection.