I haven't read this meta-analysis, so I don't know if it's any good (I have some doubts), but the headline result is entirely unsurprising given my analysis of Boulware et al.'s study, which I showed actually suggested a modest prophylactic effect of HCQ. https://necpluribusimpar.net/hydroxychloroquine-significance-testing-and-the-misinterpretation-of-negative-results/ https://twitter.com/BallouxFrancois/status/1311502282324946944

One reason I'm skeptical is that the fact they used a a "compound metric" of infection, hospitalisation and death suggests to me that perhaps not all the studies they included were about *pre-exposure* prophylaxis (as Boulware et al. was), which wouldn't make a lot of sense.

On the other hand, Boulware et al.'s study arguably was at least as much about post-exposure prophylaxis as pre-exposure because of a faulty design, so if the other studies included in the meta-analysis were about post-exposure prophylaxis, the result might still be meaningful