Safety of influenza vaccine during COVID-19
Joe Zein, Georgina Whelan, Serpil C. Erzurum
Abstract
Epidemic curves seen during the 1918 influenza pandemic demonstrated multiple resurgent waves caused by the lifting of control measures as the number of new infections decreased This suggests that the second wave of coronavirus disease 2019 , caused by severe acute coronavirus-2 (SARS-CoV-2), is possible in the fall of 2020. The convergence with influenza season could result in significant morbidity and mortality among susceptible individuals, such as elderly individuals and those with comorbidities. Little is known about coinfection with SARS-CoV-2 and influenza virus, or the interaction between vaccination against influenza and SARS-CoV-2. Last year's influenza vaccine was administered in 2019 antecedent to the SARS-CoV-2 pandemic, offering an opportunity to test the association between influenza vaccination and COVID-19 incidence and severity. Patients were considered to have worse outcomes from severe COVID-19 if they required hospitalization, were admitted to the intensive care unit (ICU), or died during hospitalization.