Paris (AFP)

A treatment for malaria, chloroquine, has shown signs of effectiveness against the new coronavirus, according to a preliminary study carried out in China, but several experts call for caution in the absence of further studies and because of its side effects which can be serious.

According to a Chinese study published on February 19, a clinical trial conducted in ten Chinese hospitals to measure "the effectiveness of chloroquine on the treatment of pneumonia associated with Covid-19" has given encouraging results with trials on " more than 100 patients ".

Chloroquine is an inexpensive antimalarial used for several decades and marketed in particular under the name of Nivaquine. This treatment is often recommended when planning to go to an area infested with the malaria parasite, transmitted by mosquitoes.

According to the scientists who wrote the study, chloroquine phosphate was "more effective than the treatment received by the comparison group in containing the progression of pneumonia, in improving the state of the lungs, in making the patient becomes negative for the virus again and to shorten the duration of the illness. "

For Professor Didier Raoult, director of the Mediterranean Infection Institute in Marseille and renowned specialist in infectious diseases, who relayed this study in France, the possible effectiveness of chloroquine is "excellent news".

- Caution and adverse effects -

But this opinion is far from unanimous and this potential track must be welcomed with the greatest caution, warned several other French specialists interviewed by AFP.

"You have to be extremely cautious and careful," notes François Maignen, doctor of pharmacy and public health specialist, who points out the limits of the Chinese study.

"You have to have the protocols available to know how the study was conducted, what the evaluation criteria were, the patient population", according to the usual standards for drug tests, he explains.

And "once the results are available, there must be a publication phase (...) for the data to be critically evaluated" by experts, in particular scientists from the World Health Organization (WHO), continues- he.

In the absence of solid and public clinical data, one cannot deduce from it a proof of effectiveness nor recommendations, insists François Maignen, who belongs to the collective "FakeMed", who wants to fight against false information in health.

In addition, chloroquine can even be "very dangerous in the event of an overdose", he adds, also warning against the risk of developing resistance to chloroquine.

"You have to be careful because chloroquine (...) has a certain number of undesirable effects (...), affections of the immune system, gastrointestinal affections, nausea, vomiting, liver or even haematological disorders", abounds Professor Jean-Paul Giroud, one of the most recognized specialists in pharmacology and member of the National Academy of Medicine.

It is "an important product against malaria but that does not mean that it should be used against any infection without having the security that this product leads to an improvement", he adds, noting also lack of data from the Chinese study.

"The problem is that Nivaquine is lying around in many medicine cabinets", worries the general practitioner Christian Lehmann (collective "FakeMed") who invites "not to touch Nivaquine without medical advice" because of its great toxicity.

Wednesday evening, the number 2 of the French Ministry of Health, Jérôme Salomon, added a layer during the weekly press briefing of the ministry. "Today, the scientific community is not very convinced. This does not mean that we should not be interested in it," he said, but with much more research.

Covid-19 disease has already caused some 80,000 infections and more than 2,700 deaths worldwide. Several countries are testing many molecules to find a treatment or vaccine.

© 2020 AFP