An interferon beta-1 subtype that has a methionine at position 1, a cysteine at position 17, and is glycosylated at position 80. It functions as an ANTI-VIRAL AGENT and IMMUNOMODULATOR and is used to manage the symptoms of RELAPSING-REMITTING MULTIPLE SCLEROSIS. A possible role for IFNs in prophylaxis or early treatment of COVID-19 has been suggested to compensate for possibly insufficient endogenous IFN production. However, the efficacy and safety of IFNs for treatment or prevention of COVID-19 were not established.