“In the groups who received ivermectin during trials, the drug would keep strongyloides in check. But patients in control groups would be left at the worms’ mercy. This would make it look as if ivermectin were preventing deaths caused solely by covid-19, when in fact it was preventing those caused by the parasites or by a combination of the two infections. This mechanism would explain why most studies conducted in places where strongyloides are rare showed no benefit from taking ivermectin. “Ivermectin doesn’t treat covid,” Dr Bitterman wrote. “It treats parasites (shocker) that kill people when they get steroids that treat covid.” He concluded that “taking strongyloides endemic populations, putting them into a control group with corticosteroids is a death sentence”.”
Good summary on the topic from “The Economist”: https://outline.com/TmBFfj
“In the groups who received ivermectin during trials, the drug would keep strongyloides in check. But patients in control groups would be left at the worms’ mercy. This would make it look as if ivermectin were preventing deaths caused solely by covid-19, when in fact it was preventing those caused by the parasites or by a combination of the two infections. This mechanism would explain why most studies conducted in places where strongyloides are rare showed no benefit from taking ivermectin. “Ivermectin doesn’t treat covid,” Dr Bitterman wrote. “It treats parasites (shocker) that kill people when they get steroids that treat covid.” He concluded that “taking strongyloides endemic populations, putting them into a control group with corticosteroids is a death sentence”.”
Recall that covid-19 wasn’t causing deaths in itself, and death happened only because of existing comorbidities in patients.