This paper is a good example of the conflict between science and ethics, in designing drug trials. The first sentence in their Limitations section:

Quote
Being a prospective observational study that allowed subjects to self-select between treatment vs. non-treatment instead of relying on randomization, important confounders may have been differentially present, which could otherwise explain the differences observed.

This was NOT a random blind trial. People who were taking ivermectin knew they were taking it and not placebo. Human behavior is a large factor in the spread of the virus, and the IVM participants may have just been more careful than the control group. They went to the trouble to get their medication, to take it despite some unpleasant side effects, and to keep that up during the study period. The control group decided not to take a drug that might prevent Covid, a sometimes deadly disease. They may have been equally casual about mask wearing, socializing in large groups, etc.

The conflict here is that "patient choice" is great ethically, but leads to a huge waste of resources scientifically. There is a random blind drug trial that has some results already in Brazil. It called the TOGETHER study. They tried (are continuing to try) various approved drugs to see if they are effective against Covid-19 disease (as opposed to prophylaxis). They have a very nice website. Here is their web page summarizing their results so far:

TOGETHER results

These are most interesting:

Hydroxychloroquine - Stopped for futility
Ivermectin - Stopped for futility
Fluvoxamine - Stopped for superiority

"Stopped for futility" means they reached the point where the statistics said the drug had no effect.
"Stopped for superiority" means they reached the point where the statistics said the drug was so beneficial it was unethical to continue the untreated control group.

This is the study that started the flurry of investigation and even recommendations for fluvoxamine. But more important, it is a high-quality random blind drug trial that said hydroxychloroquine and ivermectin are ineffective.

BTW: Ivermectin prescriptions are very difficult to get or to fill in the US. But fluvoxamine is used to treat OCD. Tell your doctor you are obsessed about Covid and want a fluvoxamine prescription. Get it filled at any pharmacy.

Educating anyone benefits everyone.