Preliminary results from a trial funded by the National Institutes of Health adds to a mountain of evidence showing ivermectin is not effective at treating COVID-19.
The randomized, double-blind, placebo-controlled trial – the gold standard for determining the effectiveness of drugs – is the largest of its kind studying the controversial antiparasitic.
Researchers from Duke University and Vanderbilt University recruited 1,537 participants, with about half of them receiving 400 micrograms of ivermectin for three days and the other half a placebo to see how long it took them to recover from COVID-19.
Forty-seven percent of the volunteers reported receiving at least two doses of COVID-19 vaccine. Study lead Dr. Adrian Hernandez, executive director of the Duke Clinical Research Institute, said vaccinated participants were evenly distributed in both groups.
In the eight-month study conducted during the delta and omicron waves, the authors found no statistical difference in recovery time. Patients given ivermectin recovered in about 11 days on average while patients given the placebo recovered in about 11.5 days.
“At this point, we’re not surprised,” Hernandez said. “Given these results, there does not appear to be a role for ivermectin outside of a clinical trial setting.”
There was also no statistical difference in hospitalization, emergency care, emergency visit or death between those who took ivermectin and those who took a placebo.
The findings have yet to be reviewed, appearing in the server medRxiv, and are considered preliminary but fall in line with previous studies that failed to find ivermectin beneficial to COVID-19 patients.
Ivermectin is approved by the Food and Drug Administration in tablet form for people to treat some parasitic infections. The drug also comes in a paste or can be injected to treat or prevent parasites in animals.
The drug was not frequently used in Americans before the pandemic because ivermectin is prescribed in humans to treat specific parasites not common in the US But fueled by desperation and disinformation, it caught on as an alternative COVID-19 treatment, particularly among those who refused to be vaccinated.
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Hundreds of doctors continue to prescribe the drug to treat COVID-19 patients despite warnings from health experts.
“Most of us have really repudiated its use for COVID-19. It’s frustrating that people continue to prescribe it and direct people away from proven therapies … I don’t know what more we can do, ”Dr. Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security, said in February.
SingleCare, a free prescription savings service, reported a 90% increase in ivermectin prescriptions filled January to June when compared to the same time last year. The company also reported fills spiking in August 2021, December 2021 and January 2022, correlating with the delta and omicron waves, respectively.
Many of the doctors who prescribe ivermectin follow treatment guidelines set by an organization called the Front Line COVID-19 Critical Care Alliance, which promotes the controversial drug along with other unproven therapies.
The FLCCC did not immediately respond to ‘s request to comment on the new findings.
Despite the mounting evidence against ivermectin, Hernandez said his team will continue to research the medication and its effect on COVID-19 recovery and hospitalization. They’re currently studying a higher dose of 600 micrograms for a longer duration, six days instead of three.
“The higher dose and longer duration has not been studied and that has been some of the critiques” from ivermectin proponents, Hernandez said. “We want to have evidence and answer these questions with the best possible design and rigor that’s necessary for people to make informed decisions. ”
Follow Adrianna Rodriguez on Twitter: @AdriannaUSAT.
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