13 myths about ivermectin that just won't die
Sadly, the conversation has not progressed much since 2020
During the COVID-19 era, there was a fierce debate over whether ivermectin- a cheap, off-patent drug- was effective at treating COVID-19.
Some frontline doctors reported that it was highly effective, and numerous trials showed it having a positive effect. But media outlets spread narratives that the studies were fraudulent, and that newer, “better” trials showed that it didn’t work. On top of that, youtube and social media companies censored any content reporting positive effects of ivermectin against COVID-19, calling them “disinformation.”
Unfortunately, this made it nearly impossible to tell what was going on, and numerous myths surrounding ivermectin persist today.
It’s time for these myths to be dispelled.
Myth # 1- Ivermectin is primarily veterinary, or “horse dewormer”
Despite the fact that billions of doses of ivermectin have been given to humans since the 1980s, the media recently depicted ivermectin as primarily a veterinary medicine.
Here are various media outlets calling ivermectin “horse dewormer”:
It probably didn’t help that the FDA tweeted this:
Sure, ivermectin’s been used in animals like horses and cows, but as mentioned earlier, billions of doses have been given to humans, primarily as an anti-parasitic. It’s an FDA-approved drug that’s on the WHO list of essential medicines, which are medicines that the WHO has deemed to be the most effective and safe at meeting the most important needs of humans.
Its discoverers, William Campbell and Satoshi Omura, won the Nobel Prize for discovering and developing avermectin, which Campbell and associates modified to create ivermectin. They most certainly didn’t win the Nobel Prize for a medicine that was primarily veterinary.
Doxycycline is an antibiotic that’s given to humans, but also dogs. We don’t call doxycycline a dog antibiotic.
Myth # 2- Ivermectin can only be an “anti-parasitic”
There’s this false idea that because ivermectin is an “anti-parasitic,” it would be implausible for it to also be an anti-viral.
This is misguided. First of all, one can make the argument that viruses are parasites. But more to the point, it’s not unusual for molecules to have broad spectrum effects that work against different types of organisms.
For example, azithromycin is well known as an antibiotic that can treat many different types of bacterial infections. However, it also acts against protozoa like Toxoplasma gondii (more here, here, here), Plasmodium berghei (see here), and the fungi-like Aspergillus species (more here). It also has anti-inflammatory properties (more here), and seems to help with viral infections by modulating the host’s immune response against them (more here).
Then there’s azadirachtin, a natural pesticide derived from the neem tree. Azadirachtin is well known among gardeners as an insecticide, but it also works against some fungi (more here and here), and nematodes (more here and here).
In fact, there’s a term, “broad-spectrum therapeutic” (BST), which is for antimicrobials that are active against multiple pathogen types (more here). “Drug repositioning,” or drug repurposing, is a strategy to identify new uses for drugs that are already approved for the treatment of a disease.
Here’s the repositioning history for nitazoxanide, which was originally used as an anti-parasitic, but is now understood to have a much broader range of activities:
Here are more examples of drugs that have been “repositioned” or repurposed:
By the way, there are multiple studies showing ivermectin having antiviral activity, the earliest of which go back to 2012:
2020: Inhibition of Human Adenovirus Replication by the Importin α/β1 Nuclear Import Inhibitor Ivermectin
There are others. This was just the result of a quick search.
Myth # 3- There’s “no plausible mechanism of action” against COVID-19
Some have mistakenly claimed that there is “no plausible mechanism of action” of ivermectin against SARS-CoV-2 or COVID-19.
This is false. There are plausible mechanisms of action, and these are discussed here:
The mechanisms of action of ivermectin against SARS-CoV-2—an extensive review
The broad spectrum antiviral ivermectin targets the host nuclear transport importin α/β1 heterodimer
Ivermectin, antiviral properties and COVID-19: a possible new mechanism of action
But even if there weren’t any known or plausible mechanisms of action for how ivermectin could work against COVID-19, that wouldn’t imply anything about its efficacy against COVID-19.
We routinely use drugs without understanding their mechanism of action.
Here’s a list of drugs where the mechanism of action is unknown or unclear: Drugs with unknown mechanisms of action
The list includes paracetamol, commonly known as Tylenol. More on that here: Paracetamol (acetaminophen): A familiar drug with an unexplained mechanism of action
Despite being in clinical use for over a century, the precise mechanism of action of this familiar drug remains a mystery.
In fact, we don’t fully understand ivermectin’s mode of action against worms either, though nobody doubts that it works against worms. See this review article from 2017: Ivermectin – Old Drug, New Tricks?
While the efficacy of IVM in treating a broad spectrum of parasitic infections is well established, its mode of action is less clear.
This article says similar things: Ivermectin: enigmatic multifaceted ‘wonder’ drug continues to surprise and exceed expectations
Ivermectin’s mode of action against parasites in the human body remains to be clarified. There is a substantial disparity between maximum plasma concentrations after ivermectin administration and the concentrations needed to induce paralysis in microfilariae.
Myth # 4- Ivermectin is unsafe
Ivermectin is an incredibly safe drug. In some countries it is sold over the counter.
As mentioned earlier, billions of doses have been given to humans since the 1980s. Despite such a high number of doses, there are only a little over 7000 reports of adverse events from taking ivermectin in the WHO’s Vigiaccess database.
According to this review on the safety of ivermectin, adverse effects from ivermectin are “infrequent (< 2-5% of treated patients) and mild to moderate” and “the clinical experience accumulated over the years showed these severe adverse events are unequivocally extremely rare.”
Myth # 5- Ivermectin studies are particularly fraudulent
Gideon Meyerowitz-Katz is one of a few members of a “fraud squad” that has spread the idea that ivermectin literature is “full of fraud”:
In October 2021, the BBC published an article that featured him and other members of the “fraud squad.” That article gave the impression that ivermectin studies, especially the ones that showed ivermectin working against COVID-19, were particularly fraudulent or dodgy:
Now, any body of scientific literature on a topic that gets large enough will probably have some fraud. Is ivermectin literature particularly fraudulent, compared to that baseline?
It’s estimated that “about 20% of trials are false,” at least according to this BMJ article. According to John Ioannidis, that percentage may even be higher.
If we take the accusations of the “fraud squad” at face value, we end up with about 18% of ivermectin studies being potentially fraudulent. That’s actually a bit below the expected baseline of fraud, if we go by the 20% quoted in the BMJ article. More details on that can be found here and here:
These are, of course, all just estimations. But the information we have available to us suggests that ivermectin literature isn’t out of the ordinary when it comes to fraudulence levels.
Myth # 6- The evidence that ivermectin works is only anecdotal or observational
Some people have this notion that all or most of the evidence for ivermectin working for COVID-19 is only anecdotal or observational.
First of all, anecdotal or observational data is evidence, and the observational evidence for ivermectin working in India’s Uttar Pradesh, which has a population of over 241 million people, should not be ignored (more here, here, and here).
Secondly, it’s simply false that most of the evidence is anecdotal or observational. As of today there are 46 randomized controlled trials studying the effect of ivermectin on COVID-19:
By the way, in the figure above, the studies with green are ones that show ivermectin improving outcomes among COVID-19 patients.
Myth # 7- All the “best” studies showed that ivermectin didn’t work against COVID-19
Some people were fed a narrative that the largest or “best” studies showed that ivermectin didn’t work.
Those studies got a lot of media attention, despite fatal flaws in their design, or conflicts of interest. They were also almost always portrayed as showing that ivermectin didn’t work, even when their underlying data was positive for ivermectin.
The TOGETHER trial
One of those trials, was the TOGETHER trial. This trial got a lot of attention in the media:
However, it had fatal flaws:
They seriously underdosed patients with higher BMI, which were the very people most at risk from COVID-19. Around half the men, as well as a significant proportion of women, were likely underdosed.
The trial took place in Brazil, where ivermectin is available over the counter. The area where the trial took place also seemed to be experiencing a surge in ivermectin sales at the time. Despite this, the trial did not exclude all patients that had recently taken ivermectin. This means that people in the control group could have taken ivermectin recently, which would dilute any signal of the drug’s effectiveness. More on that can be found here and here:
Their Data and Safety Monitoring Committee, which is supposed to be an independent monitoring board, was composed of people with conflicts of interest; members included people who had financial ties to the company behind the trial, or were involved in the design of the trial (more here).
The trial registration states that data was to be available upon request, but requests for access to their data have still gone unanswered.1
The patients were not properly randomized; compared to people recruited for the placebo group, the people who got ivermectin were much more likely to have been recruited during a time when a more deadly variant of SARS-CoV-2 (Gamma) was circulating in the region at the time.2 More here.
The trial was not properly blinded (see the first point here).
Even the FDA and NIH had “concerns about the conduct of the TOGETHER study” (more here).
The authors of the paper stated that “treatment with ivermectin did not result in a lower incidence of medical admission to a hospital due to progression of Covid-19…” but this was incorrect. “Medical admission to a hospital”, aka hospitalization, was actually 17% lower in those treated with ivermectin. This is from their very own table of results (circled in red):
There were many other issues, like conflicting or impossible numbers in their data, missing data, conflicting descriptions, and conflicts of interest, discussed more here and here:
The ACTIV-6 trial
Just like with the TOGETHER trial, the paper for the ACTIV-6 trial reported conclusions that did not match their own data.
The trial’s results were actually strongly positive for ivermectin; they reported that the “posterior probability of improvement in time to recovery” in those treated with ivermectin was .91. In other words, there was a 91% probability that ivermectin helped with improving time to recovery:
In this double-blinded, randomized, placebo-controlled platform trial conducted in the US during a period of Delta and Omicron variant predominance, and that included 1591 adult outpatients with COVID-19, the posterior probability of improvement in time to recovery in those treated with ivermectin vs placebo had a hazard ratio of 1.07, with a posterior probability of benefit of .91. This did not meet the prespecified threshold of posterior probability greater than .95.
Bizarrely, they followed this up by saying that this did not meet a “prespecified threshold of posterior probability greater than .95.” First of all, there’s no evidence this was a prespecified endpoint. But what’s strange is their use of an arbitrary cutoff point of .95, when they were using Bayesian statistics. Under the Bayesian framework there’s no need to meet some prespecified cutoff or threshold of “statistical significance.”
The main point is that despite finding a 91% probability of efficacy, they concluded that “these findings do not support the use of ivermectin in patients with mild to moderate COVID-19.”
Mind you, this was despite the many irregularities in trial design that worked against ivermectin, like the fact that they underdosed their patients and treated them late; patients were treated a median of 6 days late, with 25% of patients with a treatment delay of 8 days or more. Plus patients could opt out of a drug if they did not feel it worked; meaning, they were not truly randomized. More on that here:
What’s also strange, is that partway through the trial, as was reported here, the researchers invented a new, self-reported primary endpoint, “recovery time,” which had to do with the time it took for patients to no longer felt like they had symptoms.
There were also conflicts of interest: the ACTIV executive committee was previously chaired by employees of J&J and NIH, and is now chaired by employees of Pfizer and NIH. Other members of the committee were from NIAID, FDA, and Pfizer. More here:
Anyway, this didn’t stop the media from proclaiming to the world that this trial had showed ivermectin failing once again:
It was announced that ivermectin was “still on a losing streak,” and this was the “final nail in the coffin for ivermectin,” etc. etc.
Again, they didn’t talk about the flaws of this trial, or how their data actually showed positive results for ivermectin. More on this trial can be found here, here and here.
Intriguingly, the design flaws of the ACTIV-6 trial were similar to those of the TOGETHER trial:
We could talk about the flaws of other trials, but you probably get the point: media depictions of trials are utterly unreliable.
Myth # 8- The dosage required for ivermectin to have antiviral activity is not achievable in humans
In June 2020, a study tested the antiviral activity of ivermectin against SARS-CoV-2. This was an “in vitro” study; aka, one that involved testing cells in culture, like in test tubes or petri dishes. This study found that a ~2 μM concentration of ivermectin inhibited SARS-CoV-2 virus by 50%, in the cells they were testing.
Since then, some people assumed that in order for ivermectin to work against SARS-CoV-2 in humans, it was necessary to reach this concentration in blood plasma. This led to the mistaken belief that ivermectin couldn’t work against SARS-CoV-2 because that concentration was not achievable in human plasma.
For example, Derek Lowe, a science writer for Science, made this claim here: What's Up With Ivermectin?
This was based on mistaken assumptions. One of the authors of the June 2020 study, has since spoken out and made it clear that their in-vitro test was not an effective way to determine an effective dose in humans. For one, lungs would theoretically accumulate higher concentrations of ivermectin compared to plasma. Plus, the types of cells used in their test, Vero (African green monkey kidney) cells, were particularly susceptible to SAR-CoV-2.3
More details can be found here:
Misconceptions about ivermectin dosing
Quick intro to ivermectin Ivermectin is a broad spectrum drug that’s been widely used as an antiparasitic for decades. Since 2012, there have been multiple studies indicating that it has antiviral properties as well. For a few examples, see here, here
Myth # 9- If ivermectin did have some effect against COVID-19, it’s because of its action against worms
There’s a hypothesis that ivermectin isn’t actually effective against COVID-19 directly, but appears to be effective in areas where there is a high prevalence of intestinal worms; in other words, ivermectin’s action against parasitic worms helps COVID-19 patients by eliminating their worm infections.
This hypothesis was first put forward by Avi Bitterman, and popularized by Scott Alexander’s essay here. Among some folks in the rationalist community, as well as certain pundits, this became the definitive resolution to the question of why ivermectin appeared to be effective against COVID-19 (examples here and here).
This hypothesis is full of problems, or weak, at best. For one, if it were true, we’d expect that the control groups of studies that took place in areas with high-prevalence of worms, would have higher death rates than the control groups of studies that took place in areas with low-prevalence of worms. However, that’s not the case.
There are many other problems with this hypothesis, and more on that can be found here:
And here:
By the way, Scott Alexander has since said that he's lowered his credence in this hypothesis, and "probably overestimated how important it was." In his original post, he wrote that he had 50% confidence in the hypothesis, but has since lowered it to "more like 35%." See Section IV ("Worms") here.
Myth # 10- The doctors that promoted ivermectin for treatment of COVID-19 are “fringe”
This directory lists many providers that support the treatment protocols of the FLCCC, an organization that has promoted ivermectin for the treatment of COVID-19. This directory likely undercounts the true number of doctors that have used or advocated for the FLCCC protocols.
Among those that support the use of ivermectin as a treatment for COVID-19 are highly published and world renowned critical care physicians and scientists.
They include Dr. Paul Marik, who has written over 500 peer-reviewed journal articles and been cited over 43,000 times in peer-reviewed publications, and Dr. Tess Lawrie, a world-renowned data researcher whose research consulting group has helped develop guidelines for organizations like the WHO, as well as various European governments. Her peer-reviewed publications have received over 5000 citations.
Although the number of peer-reviewed publications is not a good metric for how “good” someone is as a doctor or scientist, it is one of the primary metrics for how “established” someone is. And by that metric, we can hardly call these people “fringe.”
By the way, Wikipedia cannot be relied upon to give an unbiased view of these people. Even one of the co-founders of Wikipedia, Larry Sanger, has denounced Wikipedia.
Myth # 11- Ivermectin overdoses were backing up hospitals and poison centers
In 2021, some media outlets ran false stories that painted a picture of dumb right-wing hicks that had gotten sick taking horse dewormer. Most famously, in September 2021, Rolling Stone ran this article:
They “reported” that there were so many dumb idiots in Oklahoma who had taken horse dewormer that gunshot victims were left waiting in line to get into the hospital. Other media outlets, like Daily News and The Guardian, ran with their own version of the story.
But the story turned out to be completely bogus.
Rolling stone eventually put out an “update” from the Oklahoma hospital, which stated that the doctor quoted had not even worked at that location in over 2 months. Even worse, the hospital had not even treated any patients due to complications related to taking ivermectin. Rolling Stone put out a second update noting that, “Rolling Stone has been unable to independently verify any such cases.”
But the damage was done: the “updates” didn’t get nearly the same amount of attention as the original bogus article.
Then there was the narrative that poison centers were drowning in calls about ivermectin horse paste overdoses. Apparently calls to poison control in Alabama “more than doubled.” Calls to poison control in Texas increased by 590%, and by 800% in Minnesota.
What got lost in the narrative was the fact that the number of calls was tiny. The jump in Minnesota was from one call to nine. In Alabama, the “increase” was from 5 in 2019, 12 in 2020, to 24 in 2021. And of the 24 calls in 2021, only 15 had been related to treatment of COVID-19 (more here).
Myth # 12- The fact that Merck threw ivermectin under the bus is evidence against ivermectin
As mentioned earlier, the discovery and development of ivermectin was led by Satoshi Ōmura4 and William Campbell, who was with the pharmaceutical company Merck & Co. at the time. Ivermectin was Merck’s drug, at least until its patent expired in 1996.
On February 4, 2021, Merck issued a statement that there was “No scientific basis for a potential therapeutic effect against COVID-19.”
Some people think that this is some kind of “smoking gun” evidence for ivermectin not working against COVID-19; after all, why would Merck disparage their own drug?
This overlooks the fact that Merck would not have been able to make much money off of it. Ivermectin is an old, cheap, off-patent drug, meaning: anyone can make or sell it. Meanwhile, Merck were releasing their new, patented drug for COVID-19, molnupiravir, which was predicted to make billions of dollars in sales for Merck. Ivermectin sales would have eaten into their profits.
Moreover, while off-label prescribing is widespread and completely legal, it is illegal for a pharmaceutical company to promote off-label prescribing; this is called “off-label marketing.”
Myth # 13- Ivermectin was not suppressed, and/or there was no reason for ivermectin to be suppressed
We’ve already seen how media outlets were spreading ridiculous narratives about ivermectin. But behind the scenes, there were subtler ways that ivermectin was sabotaged.
For example, on December 8, 2020, Dr. Pierre Kory gave a Senate testimony describing the evidence supporting ivermectin. This quickly went viral, but Youtube removed the video of his Senate testimony. Youtube also routinely removed videos promoting ivermectin, including a video by Noble Prize winner Dr. Satoshi Omura.
Then we saw how a researcher, Andrew Hill, was caught on camera admitting that he had been pressured to downplay the evidence for ivermectin in one of his papers, even though he thought that the data showed that it worked; he admitted that someone from his sponsoring organization wrote the conclusion for his paper.5 For more on that see here, here or here.
In March of 2021, the FDA, the European Medicines Association (EMA), and the WHO all issued statements advising against the use of ivermectin for COVID-19.
In August of 2021, the CDC sent out a warning about ivermectin, though it only provided two examples of anyone having a problem with the drug: someone who took too much of on an animal version and someone who took too many ivermectin tablets bought on the internet (both recovered).
Top medical journals also suppressed the evidence of efficacy of ivermectin for COVID-19:
Doctors were also suspended or driven out for supporting the use of ivermectin for COVID-19. For example, see the case of Dr. Mary Bowden, or how The American Board of Internal Medicine went after Dr. Paul Marik, and Dr. Pierre Kory.
More examples of how ivermectin was suppressed can be found here:
To some, it may seem like all these entities conspired to suppress ivermectin. But that’s not even necessary; many of these organizations had interests that were aligned.
As mentioned earlier, ivermectin is a cheap, safe, off-patent drug. If it had been widely deployed as an effective treatment against COVID-19, it would have directly competed with patented COVID-19 treatments, as well as vaccines. It’s easy to imagine that more people would have opted out of the novel COVID-19 vaccines in such a scenario; after all, ivermectin had a much longer track record of safety. It might also have made it more difficult for vaccines to receive emergency use authorization.
Pharmaceutical companies therefore had billions of dollars at stake. There’s no doubt that there was an incentive to suppress drugs like ivermectin, as well as other off-patent medications. Government health agencies like the CDC and FDA, which receive large sums of money from pharmaceutical companies, had similar incentives. The FDA used to be entirely funded by taxpayer money, but today nearly half of the FDA’s budget comes from the very companies it is supposed to regulate, and there’s a “revolving door” between Pharma and regulatory agencies.
Example:
For more on that see:
The CDC is being influenced by corporate and political interests
Centers for Disease Control and Prevention: protecting the private good?
Hidden conflicts? Pharma payments to FDA advisers after drug approvals spark ethical concerns
The Cost of Capture: How the Pharmaceutical Industry Has Corrupted Policymakers and Harmed Patients
Thick as Thieves? Big Pharma Wields Its Power with the Help of Government Regulation
PFIZER’S YEARS-LONG COZY RELATIONSHIP WITH CDC OFFICIAL REVEALED
For more on the WHO see:
Covid-19, trust, and Wellcome: how charity’s pharma investments overlap with its research efforts
Private research funders court controversy with billions in secretive investments
WHO: Do financial contributions from ‘pharma’ violate WHO Guidelines?
WHO Voluntary contributions by fund and by contributor, 2020
For more on how pharmaceutical companies and health agencies have enormous influence over the media, see here:
And for more on how pharmaceutical companies have enormous influence over medical journals, see here:
Scope and impact of financial conflicts of interest in biomedical research: a systematic review
Uneasy Alliance — Clinical Investigators and the Pharmaceutical Industry
This was also echoed by Dr. Marcia Angell, Harvard Medical School faculty member and former editor-in-chief of the New England Journal of Medicine: see here.
Beware the pitfalls
The purpose of this article is not to convince you that ivermectin works against COVID-19.
But if you want to have any chance at getting to the truth of this matter, you need to be aware of the myths, misconceptions, and wormy arguments out there.
Hopefully this article helps with that.
Pierre Kory has reported that even funders of the trial have been unable to access the data (more here).
This trial also studied the effect of metformin on COVID-19, and even this trial’s publication on metformin mentioned that the severity of the disease changed during this time period:
The rate of our primary endpoint occurring appears to have increased importantly from the beginning of the trial to the end of the trial. This is likely explained by the emergence of the predominant Gamma (P.1) variant during the conduct of this trial that may exhibit greater transmission and worse clinical outcomes than earlier variants.
By the way, Omura’s university, Kitasato University, asked Merck to conduct clinical trials of ivermectin for COVID-19. The company declined.
This organization was Unitaid. Unitaid was linked to the Bill and Melinda Gates Foundation, which had a lot of stake in the COVID-19 vaccines.
Thanks for this article, Joomi, beautiful work.
I used horse paste in 2021 when I caught Delta. So did my husband and eldest son. Then in July 2022 I caught Omicron, and by then I had Iverheal 12 mg tablets from an Indian supplier. I used those. For me, at 150 lbs, 36 mg/day produced dramatic relief of symptoms in about 8 hours. Best of all, ZERO side effects, and I tend to get every possible weird side effect from most meds. I cannot prove that ivermectin sped up my recovery but I use it now for any respiratory illness. It just does not seem to have a down side.
awesome aggregation / highlights of the last 3 years of the ivermectin story