The Ford study, which I pointed out in the long hydroxychloroquine thread, is not a randomized, placebo controlled study (there were several other observational ones). Now that we have had several randomized, placebo-controlled studies, I would give their results primacy because they are the least susceptible to bias.
In addition to the article I linked (which I did because it just came out), there was this randomized trial of hydroxychloroquine as post-exposure prophylaxis:
https://www.nejm.org/doi/full/10.1056/NEJMoa2016638
That's about as early as you can get (within four days after exposure, but before symptoms). That article finds:
Quote:After high-risk or moderate-risk exposure to Covid-19, hydroxychloroquine did not prevent illness compatible with Covid-19 or confirmed infection when used as postexposure prophylaxis within 4 days after exposure. (Funded by David Baszucki and Jan Ellison Baszucki and others; ClinicalTrials.gov number, NCT04308668
I would not say that the question is settled, but in randomized, placebo controlled studies, hydroxychloroquine has failed to show benefit over placebo/standard of care in a variety of different settings. There is always the possibility that it works in some peculiar circumstances that haven't been correctly tested by a randomized trial or that it has a small effect that can't quite be measured by the trial, but that is becoming less and less likely as more and more studies come up empty.
This news article in Science summarizes the emerging consensus:
https://www.sciencemag.org/news/2020/06/...t-covid-19
Quote:The results are persuading some doctors to stop using the drug for COVID-19. “The Recovery trial, in addition to the signals from other studies we have received so far, are enough to convince me to not offer hydroxychloroquine to hospitalized patients,” Nahid Bhadelia, a physician at Boston Medical Center, wrote in an email. Martin Landray of the University of Oxford, one of Recovery’s principal investigators, agrees: “If you, your spouse, your mother gets admitted to hospital and is offered hydroxychloroquine, don’t take it,” he says.
But some scientists say they want to see the full data before making up their minds. About one in four patients died in both arms of the study, Kremsner notes—a very high rate, suggesting they were gravely ill when treatment started. Nicholas White of Mahidol University in Bangkok, who also studies hydroxychloroquine, agrees the full data need evaluation. “But overall, it’s very unlikely, in my view right now sitting here, that anything’s going to change,” he says.
BC
