Findings
ASYMPTOMATIC COVID-19, DISEASE, ADVERSE EVENTS
In this randomized clinical trial including 23 959 individuals, vaccine efficacy for prevention of polymerase chain reaction (PCR)–positive symptomatic COVID-19 was 49.7%; severe disease, 76.8%; and hospitalization, 77.7% after the 2-dose regimen of FINLAY-FR-2, which improved to 64.9% for prevention of PCR-positive symptomatic COVID-19, 96.6% for prevention of severe disease, and 96.6% for prevention of hospitalization in recipients of a 2-dose regimen of FINLAY-FR-2 and a third dose of FINLAY-FR-1A. The incidence of serious adverse events was lower than 0.1%.