Chloroquine, an Anti-Malaria Drug as Effective Prevention for Hantavirus (2021)

Hydroxychloroquine, chloroquine, and mefloquine are basically something that's good to have on hand. If you're asking the question about whether it's needed, then you don't need it. Chloroquine saved my life during Covid-19 when my chest had just started to take a turn for the worse, and my fevers were also not going away. All it took was 250 mg for two days, repeated after one week. I had some mild palpitations for a month which were managed as needed with 12.5 or 25 mg atenolol. My symptoms disappeared.

I religiously tried ivermectin too another time for Covid-19, but it did nothing for me. It could perhaps help someone with a worm infection, or it's possible it works better when used together with something else. It is just dumb to lump chloroquine and ivermectin in the same group.

Chloroquine itself is mechanistically not supposed to work for Covid-19, but various agents are supposed to bypass its limitation, making it work. These agents are camostat, azithromycin, genistein, quercetin, bromelain, and barbed skullcap. I wouldn't use azithromycin though with chloroquine due to an added cardiac risk, but quercetin+bromelain should do the job quite well. Mefloquine doesn't even have such a limitation. All of this is documented in literature.

Anyway, since you don't seem to need any of it, feel free to keep looking only at the "bad preprints", and conveniently ignoring everything else. The medical system relies on you to propagate the claims that make them rich.