Ivermectin and Statistical Significance.

• Author: Hooper, Charles L.

At what point should a potential therapy be deemed effective?

Since the beginning of the COVID-19 pandemic, humanity has been searching for effective treatments and preventatives for the virus. Responses have ranged from the wearing of facemasks and "social distancing" to the development of new vaccines and treatments. Researchers have also looked at existing medications to see if they can be helpful in combating the illness.

One existing medication has received considerable attention recently: ivermectin, an antiparasitic that is widely used in the developing world. Many commentators, including several health officials, have dismissed the drug's usefulness against COVID. Yet, these dismissals seldom cite empirical evidence, or if they do, they don't detail the findings.

Ivermectin, which is the generic name for the drug, was discovered in 1975 by William Campbell of the Merck Institute for Therapeutic Research and Satoshi Omura of Kitasato University, in work that would win them the 2015 Nobel Prize in Physiology or Medicine. Merck first marketed the drug as a veterinary antiparasitic (today it is best known by the brand name Heartgard), with human applications (and the requisite government approvals, under the brand-names Stromectol and Mectizan) coming a few years later. In the developing world, the drug has proven so effective at combating parasitic illness that it is on the World Health Organization's list of essential medicines. It has been dosed four billion times to patients in Africa and Central and South America.

Ivermectin works through a variety of mechanisms to kill the targeted parasites. Some of those mechanisms have also been found to attack single-strand RNA viruses like SARS-CoV-2, which causes COVID. That led scientists to test the medication in vitro, finding that it does in fact kill the virus in cell cultures.

Because ivermectin has been around for decades, can be taken as an oral pill, is safe, and is now off-patent and therefore cheap, it would be an ideal drug to give to COVID patients--if it is, in fact, effective in the body and not just in the petri dish. Is it?

Most Medical Authorites Say No

Most medical authorities currently discourage the use of ivermectin to prevent or treat SARSCoV-2 infection. Because the drug is often used as a veterinary medicine in the United States and other developed countries, news that people were taking it to ward off COVID inspired the U.S. Food and Drug Administration last August to tweet: "You are not a horse. You are not a cow. Seriously, y'all. Stop it." More thoughtfully, the FDA posted on its website, "Currently available data do not show ivermectin is effective against COVID-19."

Likewise, on its website, the National Institutes of Health posted, "There is insufficient evidence for the COVID-19 Treatment Guidelines Panel to recommend either for or against the use of ivermectin for the treatment of COVID-19." The World Health Organization posted: "The current evidence on the use of ivermectin to treat COVID-19 patients is inconclusive. Until more data is available, WHO recommends that the drug only be used within clinical trials." The American Medical Association posted, "The American Medical Association (AMA), American Pharmacists Association (APhA), and American Society of Health-System Pharmacists (ASHP) strongly oppose the ordering, prescribing, or dispensing of ivermectin to prevent or treat COVID-19 outside of a clinical trial" (bold in original). And the U.S. Centers for Disease Control posted, "Be aware that currently, ivermectin has not been proven as a way to prevent or treat COVID-19."

Even Merck cautioned the public against the drug's use against COVID. In February 2021, the drugmaker issued a statement that included this: "It is important to note that, to-date, our analysis has identified: No meaningful evidence for clinical activity or clinical efficacy in patients with COVID-19 disease."

Yet, notice that these statements do not say ivermectin does not work against COVID. At most, they say only that, to date, research has not shown that it does work. So, what does the research show?

Early Clinical Data

At the time this article was written, the website c19ivermectin.com listed 73 clinical trials of ivermectin and COVID-19, involving 56,774 patients, as having been conducted. Thirty-one of the studies (6,828 patients) were randomized, controlled trials. Fifty-two were peer-reviewed (18,768 patients).

A few of the studies have been challenged and even retracted for shoddy work (perhaps putting it kindly), but most have not; we will look more carefully at these studies below. Still, the aggregate results are noteworthy. The treatment group had 59% lower mortality than the placebo or standard therapy control group (examined in 34 studies involving 44,061 patients), 48% lower use of mechanical ventilation (12 studies; 2,316 patients), 57% fewer intensive-care-unit admissions (seven studies; 21,857 patients), 45% fewer hospitalizations (19 studies; 11,190 patients)...