Do eosinophils exert antiviral activity in COVID-19 patients?
Anti-IL-5 treatment, which induces eosinophil deficiency, results in a higher viral load in influenza and rhinovirus infection. This might be due to the ability of eosinophils to bind and inactivate the influenza A virus and respiratory syncytial virus (RSV).53 A similar role seems possible in SARS-CoV-2 infection, where type-2 asthma patients potentially benefit from antiviral eosinophil responses. On the other hand, COVID-19 post-mortems did not show lung eosinophilia51, which argues against its local protective role in SARS-CoV-2 infection, although it is important to control for glucocorticoid-driven eosinophil reduction in these studies.50