[jstgord]

If you read the Monash paper showing Ivermectin kills Covid at high doses in-vitro, link below, it does discuss how they surveyed various well known widely available medicines against a variety of viruses in 2012 and found that Ivermectin surprisingly seems to have an effect vs several viruses, including Zika, Dengue, West Nile Virus.

.. so, later, when Covid broke they were interested to see if IVT had an effect vs Covid - under the assumption that its anti-viral mechanism was host-centric rather than virus-specific. It did, wow :

The Monash paper - https://doi.org/10.1016/j.antiviral.2020.104787

Regardless of whether IVT is ultimately found to be an effective treatment vs Covid in humans [ unclear and controversial at the moment ] it is certainly important to understand its mechanism of action, as it could give rise to a whole new class of broad-spectrum antivirals.

Another interesting paper is the Pasteur study of IVT effectiveness vs covid in guinea-pigs - https://doi.org/10.15252/emmm.202114122 [ I feel compelled to give further social proof from a big name institution, given the firestorm of social media opinion ]

I can only speculate that the trials showing both effectiveness and ineffectiveness of IVT in humans vs covid, differ so widely due to some confounding factor - the simplest which I can propose is that IVT is absorbed 2.5x more if taken with fatty food .. which is what you want to get the high doses purported to be effective vs covid .. yet, the medicine is normally taken on an empty stomach to treat intestinal parasites, so it can stay largely in the gut, and not be absorbed into the rest of the body.