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Brazil generalizes its use and US President Donald Trump says to take it every day, but a new study indicates that it increases the risks of premature death. What is known about chloroquine and hydroxychloroquine, presented by some as a miracle treatment against COVID-19?

What is it?

Chloroquine has been prescribed for several decades against malaria, a parasite transmitted by the mosquito.

Its best-tolerated derivative, hydroxychloroquine (HCQ), is prescribed against lupus or rheumatoid arthritis.

These well-known and inexpensive molecules have raised high hopes, especially in Africa. But they are far from the only ones to be tested. More than 800 clinical trials seek to evaluate dozens of potential treatments, according to The Lancet medical journal.

Hydroxychloroquine has known, since the end of February, an unprecedented notoriety since Professor Didier Raoult, from the Institute and University Hospital for Infectious Diseases in Marseille, released a small, little detailed Chinese study, which stated that chloroquine phosphate showed signs of efficacy in SARS-Cov2 patients.

The effervescence around hydroxychloroquine intensified when Trump began taking it daily, as a preventive measure.

In Brazil, President Jair Bolsonaro is convinced of its effects, to the point that the Ministry of Health recommended its use on Wednesday for all mildly affected patients.

Beyond the political arena, hydroxychloroquine became a highly publicized topic of public and political debate, sparking heated exchanges in the media and fierce bottlenecks on social media.

Hydroxychloroquine: effective against COVID-19?

The hypothesis of an action of these molecules against the new coronavirus comes from the fact that their antiviral properties demonstrated – in vitro or in animals, and on different viruses – sometimes positive results.

The studies also demonstrated in vitro effects for SARS-Cov2, but scientific in vitro results are often not found in vivo in humans.

Regarding human efficacy against SARS-Cov2, there is no scientific consensus due to a lack of sufficient setbacks and of studies carried out according to the usual rules: randomization (patients chosen by lottery), control group (some patients receive treatment, others do not). ), double blind (patients and doctors do not know who took the treatment and who received the placebo).

Furthermore, most of these studies are performed on a limited number of patients. Finally, a study should be published in a scientific journal after a critical rereading and subsequent validation by other scientists, independent of those who performed the tests.

To date, there are no studies that meet all of these criteria at once, and many contain more or less important methodological biases.

Raoult published several studies that, in his opinion, show an efficacy of the hydroxychloroquine associated with an antibiotic, azithromycin. For him, the health emergency justifies that this drug be widely given.

In their third study, which covered more than 1,000 patients, after 10 days, 9 out of 10 (91.7%) stopped having a viral load. But this figure, like that of the mortality of treated patients, is comparable to that observed in the case of a natural evolution of the disease.

Among the methodological biases of this study, pointed out by other scientists, one of the main ones is that there is no control group, which prevents demonstrating anything about the efficacy of HCQ.

Furthermore, 95% of the treated patients showed no signs of severity. Therefore, like most patients, they could have spontaneously healed.

A study conducted in New York hospitals and published in early May in the American journal NEJM shows that hydroxychloroquine has not significantly improved or impaired the condition of critically ill patients.

Two studies, one Chinese and one French, published last week, confirm that HCQ does not significantly reduce the risks of admission to resuscitation or death in hospitalized patients with COVID-19 pneumonia.

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Another study, with data from 96,000 patients, published Friday in The Lancet, concludes that neither chloroquine nor HCQ is effective against COVID-19 in hospitalized patients, and that these molecules even increase the risk of death and cardiac arrhythmia. .

This is the “first large-scale study” to show “solid statistical proof” that these treatments “do not benefit COVID-19 patients,” said lead author Dr. Mandeep Mehra, professor of medicine at Harvard Medical. School.

The risks

Chloroquine, especially, but also hydroxychloroquine, are medicines whose side effects can be important and even serious.

The French drug agency ANSM especially warned of the cardiac risks associated with the combination of HCQ and azithromycin.

The Swedish Medicines Agency banned the prescription of chloroquine and hydroxychloroquine for COVID-19 on April 2 due to insufficient data on its safety.

Because the knowledge is too limited, the European Medicines Agency considers that these medicines should only be “used for clinical trials or emergency programs”, within the framework of strict protocols validated in each country.

Similarly, the study published May 22 in The Lancet recommends restricting these treatments to clinical trials.

Who uses it and in which case?

These molecules – usually HCQ and more rarely chloroquine – are administered to patients with COVID-19 in many countries.

But often the framework is limited to clinical trials and generally within the hospital, and only for severe cases.

But, since Wednesday, the Brazilian Ministry of Health recommends the use of chloroquine and hydroxychloroquine for patients with COVID-19.

However, “as there are no complete studies demonstrating the benefits of these molecules for the treatment of COVID-19, (…) the decision to prescribe them rests with the doctor, with the patient’s consent,” adds the ministry.

In the United States, the drug agency (FDA) authorized the use, but only in the hospital “in an adapted way, when a clinical trial is not available or is feasible.” And not preventively, as Trump brags about it.

Aside from clinical trials, France restricted the use of hydroxychloroquine to the hospital only and only for severe cases by the collegiate decision of the doctors.

In Senegal, many coronavirus patients received hydroxychloroquine in hospitals.

It is also used in Chad, Syria, Algeria, and Morocco. In Russia, it is distributed to hospitals to treat patients who tested positive or suspected to be infected.

The European trial (Discovery), which tests four treatments, including hydroxychlochloquine, and which raised high hopes, is more complicated than expected, especially due to a lack of patients.

You probably won’t jump to conclusions for several weeks.

In any case, despite high hopes, a “miracle molecule” cannot be expected. Otherwise, researchers who started trials earlier in China and Italy “would have already found it,” Professor Florence Ader, who leads the study, warned on May 7.