Covid. Merck’s pill is blamed for accelerating virus mutations

Does Merck’s anti-covid pill risk making the epidemic worse? The researchers say that this treatment promotes mutations in the virus, with the risk, currently theoretical, of producing dangerous variants. “Molnupiravir treatment left a visible footprint in the global sequence databaseof the virus’s genome, concludes a study published Monday in the journal Nature .

Molnupiravir is a drug developed by the American pharmaceutical giant Merck (internationally known as MSD). Hitting the market in 2021, it was the first anti-covid pill, a significant advance for a pharmaceutical arsenal that until then consisted only of vaccines and treatments that required complex intravenous administration.

But the addictive drug, marketed under the name Lagevrio, quickly became the subject of criticism. They were partly aimed at its limited effectiveness, particularly compared to its main competitor, Pfizer’s Paxlovid, which quickly joined it on the market. Above all, his modus operandi has caused great reluctance. Unlike other antivirals such as Paxlovid, Lagevrio works by integrating directly into the virus’s genome. The goal is to induce a series of increasingly disruptive mutations that eventually lead to the elimination of the virus in the body. But researchers, since its inception, have estimated that this mechanism may contribute to the generation of mutated viruses that can be transmitted from one individual to another.

Special “signature”

This risk contributed to some reluctance on the part of health authorities, such as the American FDA, which approved the drug by only a small majority, or the French High Authority for Health (HAS), which rejected it entirely. It is in this context that the study published on Monday comes as Merck’s pill’s star has faded due to poor efficacy, but it is still widely prescribed in some countries, especially in development.

The researchers looked at a huge database called Gisaid, which brings together the genomes of viruses collected from many patients around the world. For them, the conclusion is clear: the use of molnupiravir is associated with the occurrence of specific mutations. They noted a “the signature” especially at the time when the pill started to be prescribed in some countries. In contrast, it is almost absent in places where the treatment has not been established.

In summary, this treatmentcan produce viruses that have mutated significantly and that remain viable or, in some cases, even transmissibleOne of the authors, geneticist Theo Sanderson, explained to AFP. These findings have been denied by Merck. According to the American laboratory, the study only highlights the correlation without making it possible to establish a causal link between its treatment and these mutations. The authors rely on “associations of circumstances“, the group told AFP.

There is no immediate risk

The fact remains that the study convinces several researchers who did not participate in it, such as virologist Stephen Griffin, who praised the work of the British Science Media Center (SMC).well conducted and of exceptional importance“. Like the authors of the study, he insists on one point. the mutations found did not appear to be particularly dangerous or virulent in themselves. “But these results have important implications for the rest of the epidemic,” warns Stephen Griffin.

Indeed, any phenomenon that accelerates virus mutations eventually threatens to produce more dangerous variants or, as Omicron was when it first appeared, significantly more transmissible than its predecessors. In this context, should we stop the designation of obsessive-compulsive? The authors of the study are careful not to comment, staying on the basis of genetics and referring health authorities to their responsibilities. And for some researchers, if these results remind us of the need not to prescribe molnupiirir all the time, we shouldn’t abandon it altogether. “Of course, you should not systematically take narcotic when you are infectedconcludes Chris Butler, an infectious disease specialist at SMC. “But in some difficult cases it is a medicine that can be very helpful“.