Eosinophil Responses During COVID-19 Infections and Coronavirus Vaccination

Lindsley, Andrew W.; Schwartz, Justin T.; Rothenberg, Marc E.

Abstract Eosinophils are circulating and tissue-resident leukocytes that have potent pro-inflammatory effects in a number of diseases. Recently, eosinophils have been shown to have a variety of other functions, including immunoregulation and antiviral activity. Eosinophil levels vary dramatically in a number of clinical settings, especially following eosinophil-targeted therapy, which is now available to selectively deplete these cells. There are key COVID-19–related questions concerning eosinophils whose answers affect recommended prevention and care. First, do patients with eosinophilia-associated diseases have an altered course of COVID-19? Second, do patients with eosinopenia (now intentionally induced by biological drugs) have unique COVID-19 susceptibility and/or disease course? This is a particularly relevant question as eosinopenia is associated with acute respiratory deterioration during infection with the Severe Acute Respiratory Syndrome (SARS)-Corona Virus (CoV)-2, the causative agent of COVID-19. Third, do eosinophils contribute to the lung pathology induced during COVID-19 and will they contribute to immunopotentiation potentially associated with emerging COVID-19 vaccines? Herein, we address these timely questions and project considerations during the emerging COVID-19 pandemic.