Navarro clashed with Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases, over whether the administration should promote the use of hydroxychloroquine to treat the virus, even though the drug's effectiveness was unproven. In July 2020, Navarro touted a widely criticized study as showing that hydroxychloroquine was an effective coronavirus treatment; public health experts pointed to limitations with the study and to the fact that multiple randomized controlled trials failed to conclude that hydroxychloroquine was an effective treatment.