I think there are 2 hypothesis for HCQ. One is that it blocks autophagosome-lysosome fusion. The second is that it is a Zinc ionophore, which enables Zinc to enter cells to stop viral replication. It seems that almost all the studies are not using Zinc. Here is a retrospective observational study showing effectiveness of HCQ+Zinc. It is a mystery to me why this second path doesn’t get more attention. Quercetin is also a Zinc ionophore. So Quercetin+Zinc should also be studied.
https://www.medrxiv.org/content/10.1101/2020.05.02.20080036v...