This trial has many limitations, acknowledged by the investigators. The trial methods did not allow consistent proof of exposure to SARS-CoV-2 or consistent laboratory confirmation that the symptom complex that was reported represented a SARS-CoV-2 infection. Indeed, the specificity of participant-reported Covid-19 symptoms is low,
6 so it is hard to be certain how many participants in the trial actually had Covid-19. Adherence to the interventions could not be monitored, and participants reported less-than-perfect adherence, more notably in the group receiving hydroxychloroquine. In addition, those enrolled in the trial were younger (median age, 40 years) and had fewer coexisting conditions than persons in whom severe Covid-19 is most likely to develop,
7 so enrollment of higher-risk participants might have yielded a different result.