Remdesivir is primarily used as an antiviral medication in the treatment of severe viral infections, most notably COVID-19. It works by inhibiting the replication of RNA viruses through interference with the viral RNA polymerase, thereby reducing the amount of virus in the body. It is administered intravenously and is typically used in hospitalized patients who require supplemental oxygen but are not yet on mechanical ventilation. Remdesivir has been shown to shorten recovery time in some patients and is often used in combination with other treatments such as corticosteroids. It has also been investigated for use in treating other RNA virus infections, including Ebola and related viral diseases, though its effectiveness in these cases is more limited compared to its use in SARS-CoV-2 infections.