Hydroxychloroquine also directly inhibits heme breakdown, a weak point in malaria parasites' blood digestion.

Beyond its standard antiviral and immunomodulatory activity, it's thought that hydroxychloroquine protects red blood cells' heme molecules from having their iron ripped out by Covid.

When you're dealing with a new disease there are no best practices for treatment. This is tautologically true. That's why doctors have to use their best judgement and try different things and write down what seems to work and what doesn't. Often they get it wrong, with very bad consequences. For instance putting covid patients prematurely on mechanical ventilators had catastrophic health implications. When this became apparent ventilator policy changed. People died and now we know better. It's ugly, but that's how you learn about treating a new(ish) disease. Waiting for the results of multiple randomized controlled trials is, frankly, fantasy. Covid has almost entirely ran its course and we aren't close to having solid treatment results from randomized controlled trials. Premature and ad-hoc treatment is how we've muddled through the pandemic, and it's how we'll muddle through the next pandemic, too.

I suggest you try to get in touch with those people working in Asian sides using it as treatment. Most don't publish their results there but do use it. And you can see a significant low mortality compare to western countries that largely choose not to use it. South and Eastern Asian side has very high infection rates way more than western counterpart and yet mortality is significantly lower both in terms of absolute value or by percentage.

Off label uses of drugs has been common for decades. Trials aren't just spun up without some evidence of anecdotes to support them being worth the effort. If anything a drug with well understood side effects and a plausible method of actually being helpful is probably worth trying while formal trials can be conducted.