The use of the drug — often paired with azithromycin — has not yet been proven in clinical trials to be effective against the disease. However, given reported success in a growing number of small, non-randomized studies; as well as testimonials from doctors and patients about the use of the "off-label" drug regimen, doctors are said to be prescribing the treatment to patients who are severely ill. Anecdotally, many doctors are taking it prophylactically.

The Department of Health and Human Services (HHS) issued a statement on Sunday:

The U.S. Food and Drug Administration (FDA) issued an Emergency Use Authorization (EUA) to BARDA to allow hydroxychloroquine sulfate and chloroquine phosphate products donated to the Strategic National Stockpile (SNS) to be distributed and prescribed by doctors to hospitalized teen and adult patients with COVID-19, as appropriate, when a clinical trial is not available or feasible.