The type I interferon response in COVID-19: implications for treatment

Despite early reports to the contrary, there is increasing evidence that patients with severe COVID-19 have a robust type I interferon response, which contrasts with the delayed, possibly suppressed, interferon response seen early in infection. A robust type I interferon response could exacerbate hyperinflammation in the progression to severe COVID-19 through diverse mechanisms. Further understanding of the roles of type I interferon at different stages of infection and in patients with mild versus severe COVID-19 will provide insights for the therapeutic use of interferon administration or JAK inhibitors in patients with COVID-19. In this Comment, Jeong Seok Lee and Eui-Cheol Shin discuss contradictory results regarding the downregulation or upregulation of type I interferon responses in patients with COVID-19 and the implications for therapies that target this pathway.