your link is to chloroquine phosphate, which has a phosphate group and is only like 75% chloroquine by weight. So no, not less than half. Moreover, you are trying to compare a hydroxychloroquine dose with a chloroquine phosphate dose (active ingredient is chloroquine, not hydroxychloroquine), which is any one's guess if they even have the same mechanism of action here. Just because they both work against malaria, doesn't mean much about this virus. All in all, it is nearly useless to compare the chloroquine phosphate dose and outcomes to the hydroxychloroquine dose and outcomes.