Hydroxychloroquine for the Prevention of Covid-19 — Searching for Evidence
Myron S. Cohen
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (Covid-19), has generated a worldwide pandemic.The interruption of its spread depends on a combination of pharmacologic and nonpharmacologic interventions.Initial SARS-CoV-2 prevention includes social distancing, the use of face masks, environmental hygiene, and hand washing. 1 Although the most important pharmacologic interventions to prevent SARS-CoV-2 infection are likely to be vaccines, the repurposing of established drugs for short-term prophylaxis is another, more immediate option.Some researchers have promoted chloroquine and hydroxychloroquine for the treatment and prevention of illness from a variety of microorganisms, including SARS-CoV. 2 Hydroxychloroquine can inhibit replication of SARS-CoV-2 in vitro. 3Some observational studies have suggested benefits of hydroxychloroquine for the treatment of Covid-19, whereas other treatment reports have described mixed results. 4oulware et al. now report in the Journal the results of a randomized trial testing hydroxychloroquine as postexposure prophylaxis for Covid-19. 5This is described by the investigators as a "pragmatic" trial in which participants were recruited through social media and almost all data were reported by the participants.Adults who described a high-risk or moderate-risk exposure to someone with Covid-19 in their household or an occupational setting were provided hydroxychloroquine or placebo (by mail) within 4 days after the reported exposure, and before symptoms would be expected to develop.The