Ivermectin has antiviral effects against several distinct positive-sense single-strand RNA viruses, including SARS-CoV-2. On 10 April 2020, the FDA issued guidance to not use veterinary-grade ivermectin as treatment for COVID-19 in humans.
Ivermectin inhibits replication of SARS-CoV-2 in monkey kidney cell culture with an IC50 of 2.2 - 2.8 µM, making it a possible candidate for COVID-19 drug repurposing research. The doses used in cell culture would require 104 larger doses in humans based on this data, which does not look promising as an effective treatment for COVID-19. Such high doses of ivermectin are not covered by the current human-use approvals of the drug and could be dangerous, as the likely antiviral mechanism of action is the suppression of a host cellular process, specifically the inhibition of nuclear transport by importin α/β1.
A preprint published in April 2020 claimed benefits of ivermectin in the treatment of COVID-19, but it was a retrospective study based on questionable hospital data from Surgisphere and was withdrawn at the end of May. The preprint led to several government agencies in Latin America recommending ivermectin as a COVID-19 treatment; these recommendations were later denounced by the regional WHO office. On October 12, 2020 Peru withdrew its authorization to use ivermectin and hydroxychloroquine as COVID-19.