Ivermectin, an anti-parasitic drug used as the primary ingredient in canine heartworm preventatives, was touted as a “new tool” in the “arsenal” against SARS-CoV-2, the coronavirus strain responsible for the 2020 COVID-19 pandemic. Media publications like far-right cable channel OAN touted the drug as a “cure” that could kill the virus in “just 48 hours.”

Our analysis determined that this claim is a mixture of half-truths combined with misleading and overzealous claims.

Such claims began circulating online in April 2020 when Australian researchers with the Monash Biomedicine Discovery Institute and the Peter Doherty Institute of Infection and Immunity shared findings from an in vitro study that was in preprint and had not yet been peer reviewed by the scientific community. Similar claims made headway again in June, when the research was published in the scientific journal Antiviral Research, concluding that the FDA-approved drug ivermectin — which is most commonly used to treat internal and external animal parasites — was found to effectively stop SARS-CoV-2 virus from replicating in cells cultured in petri dishes. An in vitro study differs from an in vivo study in that the research occurs inside of extracted or grown cells cultured in a lab setting rather than in vivo, whereby the research takes place within a plant, human or animal. In vitro studies typically occur in the very early stages of research as a way to test pharmaceutical drugs or interventions before moving on to living organisms.