IFNB1 and COVID-19: Since in vitro activity against SARS-CoV and Middle East respiratory syndrome CoV (MERS-CoV) was reported for PI drugs in combination with IFNβ,[20,21] it is reasonable to suppose existence of a synergistic PI and IFNβ effect against SARS-CoV-2, as also suggested by stronger efficacy of combined IFNβ, lopinavir-ritonavir and ribavirin treatment compared to lopinavir/ritonavir alone in patients with COVID-19.[22]