Discussion
infection, infections
INFECTION, SARS-COV-2 INFECTION, INFECTIONS
Our analysis showed that the VE of 2 doses of FINLAY-FR-2 (cohort 1) in preventing symptomatic infections was 49.7% of the participants, severe cases in 76.8%, and COVID-19–related hospitalizations in 77.7%. Vaccine efficacy was higher in recipients of the third dose (cohort 2), at 64.9%, for preventing symptomatic infections and 96.6% for preventing severe cases and hospitalizations.Subunit protein vaccines are one of the most viable options for resource-limited settings due to their possible storage in refrigerators and easier distribution.Findings of a phase 3 randomized clinical trial on FINLAY-FR-2 in 44 031 participants in Cuba reported VE against PCR-confirmed COVID-19 cases to be 69.7% (95% CI, 56.5%-78.9%) for the 2-dose and 92.0% (95% CI, 80.4%-96.7%) for the 3-dose regimen.The VE assessed in this study should be interpreted in the context of the dominance of the immune-evasive Delta variant during the follow-up period.This trial benefited from a large sample size and a cohort of geographically diverse volunteers across the country. FINLAY-FR-2 is one of the only vaccines that noted the need for a third dose from its early design phases and could serve as an accessible, scalable, and affordable option for resource-limited settings that have faced challenges in accessing an equitable vaccine supply.In this study, we only excluded individuals with current COVID-19 and included others regardless of their COVID-19 history. This was recommended by the Iran Food and Drug Administration committee based on several considerations. The study started about 15 months after the onset of the epidemic in Iran. Within this period, a substantial proportion of the population contracted SARS-CoV-2 infection. However, COVID-19 history could not be verified through PCR test records, as many individuals with actual positive infection did not undergo testing at the early stages of the epidemic. Even if we had used negative antibody titers at baseline as an inclusion criterion, we would have erroneously included many individuals with a history of COVID-19 who had been infected at the early stages of the pandemic and had undetectable antibody titers due to the waning of their antibodies over time. The effect of serostatus on VE still needs further investigation. In a well-powered study conducted at the same time as our trial,