The association of previous influenza vaccination and coronavirus disease-2019

Studies have shown similarities in the structure of influenza and coronaviruses, in their binding receptors and in patterns of immune responses; and that influenza vaccine can induce cross-immunity. We examined the association of previous influenza vaccination and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, resulting in coronavirus disease-2019 (COVID-19), among 715,164 members of a health maintenance organization. In a multivariate regression model, the odds ratios for SARS-CoV-2 infection among individuals vaccinated for influenza in 2018-2019, 2019-2020, and in both seasons, compared to non-vaccinated individuals, were 0.82 (95% CI 0.68-0.99, p = .048), 0.79 (95% CI 0.67-0.98, p = .005), and 0.76 (95% CI 0.61-0.97, p = .004), respectively. Based on our findings, administration of influenza vaccine before the influenza season is highly recommended to reduce the burden of influenza, which is critical in scenarios of outbreaks of both influenza and SARS-CoV-2 infections, and also regarding its association with reduced rate of COVID-19.

Automated summary

Studies have shown similarities between influenza and coronaviruses in terms of structure, binding receptors, and immune responses. Influenza vaccine can induce cross-immunity. The research suggests that influenza vaccination could reduce the risk of SARS-CoV-2 infection, making it highly recommended before the influenza season to lessen the burden of influenza outbreaks and their association with reduced rates of COVID-19.