It's not hydroxychloroquine, per se. It's zinc. Higher concentrations of intracellular zinc makes it harder for viruses to replicate. But not all viruses, just some. Hydroxychloroquine acts as a ionophore for zinc, helping it get into your cells easier. This has been known for a super long time. But there's not a lot of science to suggest that it improves things alot. People that take zinc when they have a cold might get over it maybe 1 day faster. Is that worth it?