The final results are in, and they're incontrovertible: Ivermectin, that nostrum assiduously promoted by anti-vaccine advocates and conspiracy-mongers, is utterly useless against COVID-19.
That's the conclusion of a peer-reviewed study of more than 1,350 COVID patients treated with the drug, which is customarily used to combat parasitic diseases in humans, livestock and pets.
The study was published this week in the New England Journal of Medicine, but we reported on it last August.
That's when one of its principal investigators, Edward J. Mills of McMaster University in Hamilton, Canada, disclosed the preliminary results during a research symposium. The data he presented then are essentially the same as the final results published by the NEJM.
Mills said then that ivermectin had "no effect whatsoever" on COVID.
The trial involved 1,358 patients who presented with COVID symptoms at 12 public health clinics in Brazil in mid-2021. The subjects all had at least one medical condition that pointed to a relatively high risk of hospitalization, such as an age of 50 or higher, diabetes, hypertension, cancer or obesity.
Half were given ivermectin for three days and half received a placebo. The goal was to find whether ivermectin reduced the prospect of hospitalization or an emergency room visit due to a worsening of COVID symptoms. The bottom line is that ivermectin had no statistically significant effect.
"We did not find a significantly or clinically meaningful lower risk of medical admission to a hospital or prolonged emergency department observation ... with ivermectin," the study says.
These findings are important because ivermectin has been so assiduously touted by anti-vaxxers and credulous, irresponsible fools such as Sen. Ron Johnson, a Wisconsin Republican who has also used Senate hearings to promote hydroxychloroquine, another useless COVID treatment.
The promotion of ivermectin despite the absence of any evidence for its efficacy against COVID-19 led to a 2,400% increase in prescriptions for the drug from the pre-pandemic level of 3,600 per week to 88,000 in one week in August 2021, according to the Centers for Disease Control and Prevention.
That prompted the CDC and the Food and Drug Administration to warn Americans not to take the drug in any of its formulations to treat COVID-19.
The ivermectin craze has been costly in terms of lives and dollars.
"Unfortunately, the promotion of ivermectin, when other effective therapies were available, has likely resulted in the deaths of many Americans," says David Boulware, a University of Minnesota epidemiologist who has studied hydroxychloroquine and is a co-author of the NEJM paper.
That's especially true given that treatments with known benefits, including vaccination, are widely available.
"The continued promotion of ivermectin and other therapies without clinical benefit, such as hydroxychloroquine, reveals that the reason behind doing so is to make money, not to actually help people in need," Boulware told me. (His research showed no effect of hydroxychloroquine on COVID-19.)
Researchers at the University of Michigan and Boston University calculated in January that Medicare and private insurers wasted an estimated $130 million last year on ivermectin prescriptions for COVID.
That placed ivermectin high on the list of useless medical expenditures, the researchers said. They added that their estimate was probably conservative, since it didn't count spending by Medicaid, which also has been covering ivermectin.
Ivermectin has been the subject of determined mythmaking by its advocates. They note that its discoverers received the Nobel Prize for Medicine in 2015. What they don't mention is that the discoverers received the Nobel because of the drug's efficacy against parasites, which aren't involved in COVID.
They also point to several meta-analyses of ivermectin's effect. These are studies that compile other studies in an effort to assemble a large, statistically significant sample group.
As it happens, some of the component studies in the meta-analyses of ivermectin have been withdrawn over allegations of possible fraud or criticized for faulty methodology.
Another common claim is that the wide distribution of ivermectin virtually eliminated COVID in the state of Uttar Pradesh, India. That story has been debunked, however.
As the Australian epidemiologist Gideon Meyerowitz-Katz has pointed out, even though the Uttar Pradesh authorities directed medical officers to start giving doses of ivermectin to patients being treated for COVID-19 in August 2020, a sharp rise in cases and deaths followed anyway, then subsided.
What actually happened was that authorities began a testing and treatment campaign as cases rose, going door-to-door and advising those who tested positive to quarantine themselves and giving them a medical kit that may — or may not — have included ivermectin. But only 5 million kits were handed out among a population of as many as 250 million.
Even if the drug were 100% effective, Meyerowitz-Katz observes, "that's simply not enough to even make a dent in the state's numbers." In any event, authorities imposed a strict lockdown in April 2021, around the time that cases spiked. Uttar Pradesh also had a successful vaccination drive, with 78% of the eligible population vaccinated by the end of 2021.
By then, COVID had swept through Uttar Pradesh, suggesting that much of the population had acquired some natural immunity. Put it all together, and ivermectin's possible role in the state's experience wanes nearly to nothing.
The newly published research appears to be the most thorough trial in the ivermectin literature. The researchers investigated the drug's effect on numerous subgroups within their sample population, segmenting it by age, heart or lung condition, gender, smoking status or time since symptom onset. "We observed no benefit with ivermectin as compared with placebo among patients who began the trial regimen within 3 days after symptom onset," they wrote.
Indeed, one subgroup even showed small trend in the ivermectin group toward higher rates of ER visits and hospitalizations. Although the trend was not statistically significant, "the trend was not favorable," Boulware says. "This mirrors my University of Minnesota team's 2020 experience with hydroxychloroquine when used (for) prevention, that the people who did the best were the ones who didn't take the medicine."
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