Abstract
INTRODUCTION: Females generally have higher antibody responses to viral vaccines. Our objectives were to compare gender differences in the efficacy of COVID-19 vaccination. METHODS: Data sources: Studies from PubMed, Embase, Cochrane Central Register, Web of Science, ClinicalTrials.gov, and the World Health Organization's International Clinical Trials Registry Platform. RESULTS: We included four eligible trials; all were categorized as having a low risk of bias. COVID-19 vaccine was significantly effective in both males and females. Slightly more SARS-CoV-2 infections were recorded in females than in males, but the difference was not significant (RR 1.064 [0.888-1.274]; p = .502, I2 = 5.7%; p = .367, 643,127 participants). CONCLUSION: Despite significant biological and behavioral differences between males and females, we found no significant gender differences in the efficacy of the COVID-19 vaccines, especially in younger populations. Further pragmatic trials are needed to confirm the gender differences in protective response of different types of vaccines to different age groups.