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 several specialists explain to

    20 Minutes


    However, studies are in progress, which do not exclude moderate beneficial effects.

“More and more studies are saying: [the] 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 will Olivier Véran and the National Medicines Safety Agency ban it?


More and more studies say: #IVERMECTINE is VERY EFFECTIVE in curing all stages of # Covid_19

⚠️ this pest control is cheap, very widespread, without contraindication or harmful effects

➡️ In how many days will @olivierveran + @ansm go they ban it? https: //t.co/EKbecgji9a

- François Asselineau (@UPR_Asselineau) December 13, 2020

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 being 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 its website.

But the publication, in early April 2020, of an Australian study, fueled hopes that it would be 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 guarantee of efficacy on humans, as

Mathieu Molimard, pharmacologist and pulmonologist, member of the scientific council of the Company's website

, explained to

20 Minutes.

French Pharmacology and Therapeutics (SFPT): “What makes some people think that ivermectin could act against Covid-19 is that it is active in vitro on the Vero cell, a monkey kidney cell in culture.

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 lung epithelium cells [affected by 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" - did not in addition to highlighting, in recent months, a number of 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 around sixty residents had received ivermectin to deal with cases of scabies.

"All the cases of Covid-19 observed in nursing homes" treated "with [ivermectin] were minor, 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 [...] confirmed 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 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.

If the site "C19Ivermectin", mentioned by many advocates of ivermectin, claims to list all the studies carried out around the world going in this direction, "the vast majority are preprints, which 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 journal


, carried out 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, 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 proofreader of this article in


, 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 “Meta Evidence” site, which, thanks to the work of the University Hospital of Lyon and of the Biometrics and Evolutionary Biology Laboratory of the University of Lyon, enables the effectiveness (and the risks) of the various treatments to be verified. 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 [the first results of MedinCell] are not deleterious, but that just proves that their solution is not toxic, and nothing on its effectiveness," explains Dominique Costagliola.

"Can it have an immunomodulatory effect [which acts on the reactions of our immune system]?"

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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