Ivermectin cures COVID-19

Ivermectin cures COVID-19
	FALSE
	"Ivermectin, an antiparasitic drug, is a highly effective treatment for COVID-19 that prevents hospitalization and death, and its effectiveness has been suppressed."
Domain	Health & Medicine
Tactic	Statistical & Evidentiary Distortion; Pseudoscience / Junk Science;
Era	Current
First seen	2020
Origin	A laboratory study published in April 2020, followed by small and flawed clinical studies and online advocacy
Last reviewed	2026-10-26
	Further reading: books on Health & Medicine

The claim that ivermectin cures COVID-19 became one of the most widespread and politically charged health claims of the pandemic. Early laboratory results and a handful of small studies suggested the drug might help, and interest in it was initially reasonable. But several of the most influential positive studies turned out to be badly flawed or possibly fraudulent, and large, well-designed clinical trials conducted from 2021 onward consistently found that ivermectin did not meaningfully improve outcomes for COVID-19 patients. Demand nonetheless surged, leading to shortages, self-medication with veterinary products and an increase in poisonings.

The case shows how scientific uncertainty early in a crisis can be exploited, and how weak evidence can spread faster than strong evidence once a treatment becomes a political symbol.

Background

Ivermectin is a valuable medicine. Developed in the 1970s, it has been used to treat parasitic infections in billions of doses worldwide, including river blindness and other diseases affecting some of the poorest people in the world. Its discoverers, William Campbell and Satoshi Ōmura, shared the Nobel Prize in Physiology or Medicine in 2015. It is also widely used in veterinary medicine for livestock and pets, in formulations and doses intended for large animals.

Origin

In April 2020, researchers at Monash University in Australia reported that ivermectin inhibited the replication of the coronavirus SARS-CoV-2 in cells in a laboratory dish. The concentrations used, however, were far higher than could safely be achieved in the human body with approved doses, as other scientists soon pointed out.

Over the following months, a number of small clinical studies, many from countries with limited research infrastructure, reported benefits. Advocacy groups compiled these studies and argued that the overall evidence showed large reductions in deaths. Physicians and commentators promoted the drug in media appearances and online videos, and some governments, particularly in Latin America, distributed it widely.

How weak evidence spread

One of the most influential studies, a preprint posted in late 2020 by researchers in Egypt led by Ahmed Elgazzar, reported a roughly 90 percent reduction in deaths. It carried great weight in early meta-analyses that pooled results across studies. In July 2021, a medical student, Jack Lawrence, and other independent researchers found serious problems in the data, including duplicated patient records and patients recorded as dying before the study began. The preprint was withdrawn. Further scrutiny by a group of scientists found serious problems in several other ivermectin studies. When the flawed studies were removed from meta-analyses, the apparent benefit largely disappeared.

Researchers also noted that ivermectin might appear beneficial in places with high rates of parasitic worm infections, where treating the parasites could improve outcomes for patients receiving steroid treatment. This effect would not apply to COVID-19 itself, or to populations without such infections.

What the large trials found

Several large randomized controlled trials, the most reliable form of evidence, tested ivermectin directly:

TOGETHER (published in the New England Journal of Medicine, 2022), conducted in Brazil with more than 1,300 patients, found no significant reduction in hospitalization.
COVID-OUT (New England Journal of Medicine, 2022), in the United States, found no benefit in preventing severe disease.
ACTIV-6 (Journal of the American Medical Association, 2022 and 2023), sponsored by the US National Institutes of Health, found that ivermectin, including at higher doses, did not meaningfully shorten recovery time.
PRINCIPLE (published 2024), in the United Kingdom, found that ivermectin produced at most a small difference in recovery time and no reduction in hospitalizations or deaths.

Following these trials, major health authorities, including the World Health Organization and the US National Institutes of Health, recommended against using ivermectin to treat COVID-19 outside clinical trials.

How it spread anyway

By 2021, ivermectin had become a political and cultural symbol, associated with distrust of public-health authorities, pharmaceutical companies and vaccines. Prescriptions in the United States rose sharply. Some people took veterinary formulations intended for horses and cattle, and US poison control centers reported large increases in calls about ivermectin exposure. The US Food and Drug Administration issued warnings, including a widely shared August 2021 social media post: "You are not a horse. You are not a cow. Seriously, y'all. Stop it." Doctors who promoted the drug were sued by some patients' families, and others faced disciplinary inquiries; in 2024, the FDA settled a lawsuit brought by doctors over its messaging by agreeing to remove certain social media posts, without changing its position that ivermectin had not been shown to be effective against COVID-19.

What the evidence shows

Ivermectin is not an effective treatment for COVID-19. Large, well-conducted clinical trials have found no meaningful benefit in preventing hospitalization or death or in speeding recovery. The early impression of benefit came from laboratory concentrations far above safe human doses and from small, flawed or possibly fraudulent studies.

Lessons for readers

A result in a laboratory dish is not evidence that a drug works in people at safe doses.
Small studies are unreliable, and a few flawed studies can distort a meta-analysis that combines many.
When large, well-designed trials contradict small ones, the large trials should carry more weight.
A drug that is valuable for one disease is not necessarily useful for another.

Sources

Leon Caly et al., "The FDA-approved drug ivermectin inhibits the replication of SARS-CoV-2 in vitro," Antiviral Research 178 (2020).
Gilmar Reis et al., "Effect of Early Treatment with Ivermectin among Patients with Covid-19," New England Journal of Medicine 386 (2022).
Carolyn T. Bramante et al., "Randomized Trial of Metformin, Ivermectin, and Fluvoxamine for Covid-19," New England Journal of Medicine 387 (2022).
Susanna Naggie et al., "Effect of Ivermectin vs Placebo on Time to Sustained Recovery in Outpatients With Mild to Moderate COVID-19," JAMA 328 (2022).
Jack M. Lawrence et al., "The lesson of ivermectin: meta-analyses based on summary data alone are inherently unreliable," Nature Medicine 27 (2021).
World Health Organization, Therapeutics and COVID-19: living guideline.