I don’t have the energy to write a 5000 word blog post explaining my reasoning, but I think ≤10% chance HCQ has clinically significant effects against COVID, chances of really impressive effects even lower.
Based on these two studies, it looks almost certain that hydroxychloroquine is at least as safe as a placebo for reducing symptoms [of COVID-19], and the drug probably reduces the incidence of symptoms by a little more than 10%.
The 10% is a relative reduction, not absolute. I don’t know how Scott Alexander defines “clinically significant”. Some authors thought that “significant” meant a 50% or 90% relative reduction in cases, although I personally think that a 10% reduction matters. But I have no medical experience and no medical training. If you read Stat News, you know more about medicine than I do.
I also conclude:
It seems that hydroxychloroquine probably brings down hospitalizations, but it’s unclear by how much.
And:
If you have to go to the hospital, stop taking hydroxychloroquine.
That fact comes from a large (n = 4716) randomized controlled trial, which found that hydroxychloroquine is almost certainly unsafe for treating patients who have been hospitalized with COVID-19. The drug caused about a 7% relative increase in deaths.
Bear in mind that I redid some of the statistics from the studies because I thought they were incorrectly concluding that hydroxychloroquine had no effect. If you don’t trust my math (I wouldn’t trust a stranger’s math), you can see my work here. And I wrote the post for an audience who might not know what Bayes is.
A couple minutes after I wrote this question I found out Scott Alexander said July 29:
Last week I read the literature and concluded:
The 10% is a relative reduction, not absolute. I don’t know how Scott Alexander defines “clinically significant”. Some authors thought that “significant” meant a 50% or 90% relative reduction in cases, although I personally think that a 10% reduction matters. But I have no medical experience and no medical training. If you read Stat News, you know more about medicine than I do.
I also conclude:
And:
That fact comes from a large (n = 4716) randomized controlled trial, which found that hydroxychloroquine is almost certainly unsafe for treating patients who have been hospitalized with COVID-19. The drug caused about a 7% relative increase in deaths.
Bear in mind that I redid some of the statistics from the studies because I thought they were incorrectly concluding that hydroxychloroquine had no effect. If you don’t trust my math (I wouldn’t trust a stranger’s math), you can see my work here. And I wrote the post for an audience who might not know what Bayes is.