Hydroxychloroquine has been studied as a possible antiviral therapy for many decades. Despite showing evidence of activity against several viruses in the laboratory, it never showed success in randomized clinical trials.

In response to Donald Trump's statement on using the drug as treatment for coronavirus disease 2019 (COVID-19), quoted in Ignoring Expert Opinion, Trump Again Promotes Use of Hydroxychloroquine (April 5, 2020) by Michael Crowley, Katie Thomas and Maggie Haberman, The New York Times.