Abstract

Type I and type III interferons (IFNs) are antiviral proteins secreted from virusinfected cells. The severe course of COVID-19 is characterized by inadequately low type I and type III IFN levels during the early disease phase: SARS-CoV-2 encodes proteins capable of inhibiting the antiviral defence of the host, which enables rapid viral replication. Inhalable type I and type III IFN-s
are potential COVID-19 drug candidates that could drastically reduce the risk of developing severe disease.