Sex Disproportionality Analysis of Anaphylaxis in COVID-19 Vaccines Using World Health Organization VigiBase

Objective: Many cases of anaphylaxis has been reported to occur in humans following corona virus disease 2019 (COVID-19) vaccination.This study aimed to estimate sex disproportionality in anaphylaxis following COVID-19 vaccination and compare it with the degree of sex disproportionality of other vaccines.Methods: We used VigiBase reports recorded up to March 1, 2024.A descriptive analysis was performed to estimate reporting rates of adverse events.The reporting odds ratio (ROR) for anaphylaxis associated with COVID-19 vaccines was calculated to compare females to males and assess differences in reporting between COVID-19 vaccines and other vaccines.The ROR was computed for signal detection criteria and was presented with corresponding 95% CI.Results: Females had almost four times more cases of COVID-19 vaccines-anaphylaxis than males.In both sexes, no association was detected between COVID-19 vaccination and anaphylaxis compared to all other vaccines.However, when comparing within males and females, the ROR was 2.685 (95% CI, 2.558-2.817),confirming significant female predominance and sex disproportionality of anaphylaxis cases reported in COVID-19 vaccines.COVID-19 vaccines exhibited greater sex disproportionality than other vaccines (Rabies vaccine 2.521 [95% CI, 1.969-3.288],Tick-Borne Encephalitis vaccine 2.417 [95% CI, 1.534-3.808],Measles-Mumps-Rubella-Varicella vaccine 4.349 [95% CI, 3.934-4.808]),except Human Papillomavirus vaccine 0.377 (95% CI, 0.290-0.491).Conclusion: A sex disproportionality was observed with a notable predominance of anaphylaxis cases in females.COVID-19 vaccines showed significant sex disproportionality when compared with other vaccines.These findings underscore the importance of integrating sex-related differences into vaccine development and post-marketing safety monitoring.(PeRM 2025;17:136-145