A Cluster-Randomized Trial of Hydroxychloroquine for Prevention of Covid-19

RCT (2,314 contacts of 672 index case patients with COVID-19) found postexposure therapy with hydroxychloroquine did not prevent SARS-CoV-2 infection (18.7% vs 17.8%) or symptomatic Covid-19 (5.7% vs 6.2%, RR 0.86, 95%CI 0.52-1.42) vs usual care.

New England Journal of Medicine