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Home » Higher doses of ivermectin still useless against COVID-19

Higher doses of ivermectin still useless against COVID-19

Not trying to be repetitive, but new research shows that even higher and longer doses of ivermectin are still useless in treating COVID-19. Not a single real scientist is surprised by this, but I have to keep repeating myself because the ivermectin story won’t go away — some quack physicians are now pushing it to treat flu and respiratory syncytial virus (RSV).

This new research is another in a long line of real clinical research that has shown that ivermectin, which is best used as a horse dewormer, does not affect COVID-19. There is nothing in the mechanism of action that indicates it can destroy any virus, let alone COVID-19 (or flu or RSV).

As I always do, let’s take a look at this new study that should slam the door on anyone trying to sell the ivermectin myth to you. It is useless except for treating parasites. That’s it.

What is ivermectin?

Let me start with ivermectin itself.  It is an antiparasitic drug. It was discovered in 1975, and its first uses were in veterinary medicine to prevent and treat heartworm and acariasis. It was approved for human use in 1987 — it is used to treat infestations including head licescabiesriver blindnessstrongyloidiasistrichuriasisascariasis, and lymphatic filariasis.

William Campbell and Satoshi Ōmura won the 2015 Nobel Prize in Physiology or Medicine for its discovery and applications. The Nobel Prize was for the discoverers of such an important medicine — it is not given for the drug itself, despite wild claims on the internet.

As you will notice, there are no claims that ivermectin has any effect on viruses, including SARS-CoV-2 which causes COVID-19. The myth that ivermectin had some effect on SARS-CoV-2 was the result of an in vitro study. Of course, less than 1% of drugs that work in vitro ever end up with any clinical usefulness.

Then a series of very badly designed trials, with serious methodological issues, tried to show that ivermectin worked to treat COVID-19, but most scientists rejected those claims. However, anti-vaxxers being their usual anti-science selves, decided that ivermectin was all that was needed, not vaccines.

So, you’re wondering why we call it a “horse dewormer.” It’s because delusional people who thought it treated COVID-19 bought up the horse version of ivermectin, because they would need to see an actual doctor for a prescription for the human version, and they knew 99.9% of physicians would have laughed at them.

crop doctor with stethoscope preparing for surgery in hospital
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Another ivermectin and COVID-19 clinical trial

In a study published on 20 February 2023 in the highly respected journal, JAMA, Susanna Naggie, MD, MHS, Duke University School of Medicine, and colleagues analyzed a double-blind, randomized, placebo-controlled platform trial including 1206 US adults with COVID-19 during February 2022 to July 2022.

The researchers found no statistical difference was observed for the secondary endpoint of hospitalization, urgent or emergency department care visits, or death, at 5.7% with ivermectin compared with 6% with placebo. They also found that the median time to sustained recovery was 11 days in the ivermectin group and 11 days in the placebo group.

Essentially, there was no statistical difference in any meaningful outcome between the ivermectin and placebo groups. It didn’t matter if the patients with COVID-19 took ivermectin or a placebo, the outcomes were the same.

In an accompanying editorial, also published in JAMA, the authors wrote:

Today JAMA publishes a new trial of ivermectin treatment for mild to moderate COVID-19 that addresses the possibility that the existing literature may have missed the efficacy of ivermectin because the previously tested dose — approximately 400 μg/kg daily for 3 days — was insufficient. At a higher treatment dose — 600 μg/kg daily and longer treatment duration of 6 days, Naggie and colleagues again conclude that ivermectin is not beneficial for the treatment of COVID-19.

Decisions about what investigations to undertake must be responsive to the relative social value of continuing to reduce uncertainty around one intervention, and stakeholders must consider whether scarce time, resources, and participant effort could be better invested examining other questions

The results also match what was found in a 2022 Cochrane meta-analysis (considered the top of the hierarchy of biomedical research) of 11 eligible studies that showed no benefit of ivermectin for treating COVID-19.

This study, along with so many others, continues to provide overwhelming evidence that ivermectin does not affect COVID-19. It’s not only the lack of evidence from clinical trials that debunk this myth, it’s the lack of any reasonable and biologically plausible mechanism for ivermectin to have any effect on any virus, including SARS-CoV-2, which causes COVID-19.


I’d love to think that this study would be the final debunking of the myths about ivermectin, but I know better. Scientifically ignorant vaccine deniers will continue to push ivermectin by claiming that scientists are hiding the TRUTH™ about it.

Conspiracy theories are just the tool of science deniers to try to convince people that there is some sort of concerted effort to suppress ivermectin, so Big Pharma can make money off of vaccines. We know that the COVID-19 vaccines are safe and effective. We know that ivermectin is useless, unless, of course, you’re a horse and you have worms.


Michael Simpson

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