No, ivermectin is not a “very effective” drug against the disease.

Ivermectin (illustration). – Fotoarena / Sipa USA / SIPA

  • France, like many countries around the world, is it hiding a cheap and widespread drug that has proven to be effective against Covid-19?
  • This is supported by studies supporting the promoters of ivermectin, an antiparasitic used against scabies.
  • But this work does not prove the effectiveness of this drug against Covid-19, as explained by several specialists at 20 Minutes. However, studies are in progress, which do not exclude moderate beneficial effects.

“More and more studies [le] say: [l’]ivermectin is VERY EFFECTIVE in curing all stages of Covid-19. This antiparasitic is inexpensive, widespread, without contraindication or harmful effects. In how many days
Olivier Véran and will the National Medicines Safety Agency ban it? “

For François Asselineau, the president of the Republican Popular Union (UPR), it is obvious: this drug usually used against certain parasites would be the ideal solution to treat patients of Covid-19, as he intends to prove by relaying a long article devoted to various studies on the subject.

And he is not the only one to affirm it, since many Internet users praise – some since last spring – the effectiveness of ivermectin against Covid-19, which would be, like hydroxychloroquine in the period, attested and yet not used by health authorities.


Long before it was considered in combination with Covid-19, ivermectin was best known for its use in treatments against scabies, since it eliminates the parasites concerned, but also in veterinary care, against larvae and other lice. This drug is “safe and can be used on a large scale”, as the World Health Organization (WHO) points out.
on his site.

But the publication, at the beginning of April 2020, from an Australian study, fueled hopes of seeing it used against Covid-19. Researchers from the Royal Melbourne Hospital and Morash University showed that ivermectin had considerably reduced the burden of Covid-19 in 48 hours during their laboratory (in vitro) test on a cell.

A laboratory test on an “irrelevant model”

An encouraging result, since it reduced the replication potential of the virus, but in no way guarantees an effectiveness on humans, as explained in 20 Minutes Mathieu Molimard, pharmacologist and pulmonologist, member of the scientific council of the
the French Society of Pharmacology and Therapeutics (SFPT) : “What makes some think that ivermectin could act against Covid-19 is that it is active in vitro on the Vero cell, a cultured monkey kidney cell. But it turned out to be a very poor model for exploring SARS-CoV-2 because the mechanisms necessary for the virus to act in human cells are not present in this cell, due to an enzyme missing. “

Dominique Costagliola, Research Director at Inserm, specialized in epidemiology, confirms: “Ivermectin has been tested on vero cells, and it has been shown, as in the case of hydroxychloroquine, that this model does not ‘was irrelevant because the mechanisms of action and entry are not the same in vero cell and in pulmonary epithelium cells [toucées par le Covid-19]. »

In general, successful laboratory tests are far from guaranteeing efficacy in humans, recalls Mathieu Molimard: “The problem with in vitro is that in general, when we have an active molecule at concentrations compatible with clinical activity, there is already less than one chance in 250 that this will result in a drug at the end, ”continues the pharmacologist. And to add: “Ivermectin is the equivalent of hydroxychloroquine: like it, it works in vitro on viruses such as zyka or dengue, but has never had any clinical effect on any of these. diseases. The ivermectin trail does not have to be prioritized. “

Inconclusive observational studies

The promoters of ivermectin – authorized in particular in may in bolivia in anti-Covid treatments by the Ministry of Health, specifying that the drug had “not been scientifically validated for the treatment of the coronavirus” – have also not failed to highlight, in recent months, number observational studies supposed to prove its effectiveness in vivo (on a living organism). Like
a French study published in December 2020 based on observations made in an nursing home where about sixty residents had received ivermectin to deal with cases of scabies.

“All the observed cases of Covid-19 in the nursing home” treated “by [ivermectine] were minors, without death during the study period, while residents of “control” nursing homes (without ivermectin) […] showed a higher Covid-19 frequency and mortality. Ivermectin could have a protective role […] supported by the virological study. Despite the limitations – observational character and absence of demonstrated correlation in vitro / in vivo -, the plausibility is sufficient to carry out a randomized controlled trial in a cluster of prevention with ivermectin and Moxidectin in nursing homes ”, concluded the study, acknowledging in fact it- even the need to carry out tests on a more relevant scale to study what was only a “plausibility” carried out on a very small sample.

And the “C19Ivermectin” site, mentioned by many advocates of ivermectin, claims to list all the studies carried out around the world in this direction, “the vast majority are preprints,
that have not been validated by their peers “, Underlines Mathieu Molimard, before adding:” There was also a trial of ivermectin in hamsters, which showed that there was no antiviral activity. In the macaque either, we do not manage to have the necessary concentrations, even by increasing the doses. “

An observational study published in October in the review Chest, performed between Covid-19 patients treated with ivermectin and patients treated without this drug in Florida hospitals, is also often cited to show the supposed effects of the molecule. “But as often in this type of study, the D-0, that is to say the date on which the patient is randomized and treatment begins, is poorly defined”, explains Dominique Costagliola.

“If I start to study patients treated with ivermectin five days after their arrival at the hospital, and those without ivermectin as soon as they arrive at the hospital, their situation has bound to worsen during these days. five days apart. So I put the comparison group at a disadvantage through what is called an “immortality bias”. If I had been a proofreader of this article in Chest, it would not have been published, ”says Dominique Costagliola, who specializes in the evaluation of treatments in an observational situation.

“The study showed a decrease in mortality in the group of patients receiving ivermectin, but not in hospital stay or ventilation requirements. Above all, 40% of people who received ivermectin were also treated with corticosteroids, with proven effectiveness, against 20% in the other group so we can not conclude anything, ”adds Mathieu Molimard.

In addition, The site Meta Evidence, which makes it possible, thanks to the work of the University Hospital of Lyon and of the Biometrics and Evolutionary Biology Laboratory of the University of Lyon, to verify the effectiveness (and the risks) of the various treatments under development against Covid-19 , shows that ivermectin has not been proven. Regardless of the stage at which it is given to patients and the severity of their symptoms, the therapeutic results of the studies in question are either “inconclusive” or “risky with no proven benefit” and, in the best case, l The beneficial effect of the molecule is “suggested but not proven”.

Possible positive effects, but no “virological mechanism”

Finally, if the announcement of the French pharmaceutical company MedinCell, Thursday, December 17, of the first positive results for its clinical study aimed at “validating the safety of ivermectin in continuous administration” with a view to obtaining a preventive treatment, is rather a good sign, it does not foreshadow the effectiveness of the drug against Covid-19.

“It’s already good that [les premiers résultats de MedinCell] are not deleterious, but that just proves that their solution is not toxic, and nothing about its effectiveness, ”explains Dominique Costagliola. “Can it have an immunomodulatory effect [qui agit sur les réactions de notre système immunitaire] ? Perhaps, but it remains to be proven and this would rather concern serious patients, like Dexamethasone, which has an impact on mortality, especially in patients who are on oxygen and therefore already at an advanced stage of the disease. », Adds the specialist.

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