Does Merck’s anti-Covid pill risk making the pandemic worse? Researchers claim that this treatment contributes to the appearance of mutations in the virus, with a currently theoretical risk: giving rise to dangerous variants.
“Treatment with molnupiravir left a visible mark in global sequencing databases” of the virus genome, concludes a study published Monday in the journal Nature.
Molnupiravir is a treatment developed by the American pharmaceutical giant Merck (known internationally as MSD).
First anti-Covid pill
Launched on the market in 2021, it was the first anti-Covid pill, a notable advance for a pharmaceutical arsenal that until then was composed only of vaccines and treatments that required complex intravenous administration.
But molnupiravir, sold under the name Lagevrio, quickly came under fire. These were due in part to its limited effectiveness, particularly compared to its main competitor, Pfizer’s Paxlovid, which quickly joined it on the market.
Above all, his way of acting has caused strong reluctance. Unlike other antivirals, such as Paxlovid, Lagevrio works by integrating directly into the virus genome.
The goal is to trigger a series of increasingly disordered mutations that ultimately lead to the extinction of the virus in the body. But, since its launch, researchers estimate that this mechanism risks promoting the emergence of mutant viruses that can be transmitted from one individual to another.
Specific “signature”
This risk had contributed to certain reluctance on the part of health authorities such as the US FDA, which had only approved molnupiravir by a small majority, or the French High Health Authority (HAS), which flatly rejected it.
In this context is the study published on Monday, while the star of Merck’s pill has already faded due to its low effectiveness, but it is still widely prescribed in some countries, especially in the process of development.
The researchers studied a large database, called Gisaid, which brings together virus genomes collected from numerous patients around the world.
For them, the conclusion is clear: the use of molnupiravir is associated with the appearance of specific mutations.
They observed the appearance of a specific “signature” when the pill began to be prescribed in certain countries. On the other hand, it is almost absent in places where the treatment was not approved.
In short, this treatment “can result in viruses that have mutated significantly and remain viable or, in some cases, even transmissible,” explained one of the authors, geneticist Theo Sanderson.
Merck rejected these findings. According to the American laboratory, the study only highlights a correlation, but does not allow us to affirm a cause-effect relationship between its treatment and these mutations. The authors are relying on “circumstantial associations,” the group said.
No immediate risk
The truth is 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) as “well carried out and of exceptional importance.”
Like the study’s authors, he insists on one point: the identified mutations do not appear, in themselves, to have been particularly dangerous or contagious.
“But these results have important implications for the rest of the pandemic,” warns Stephen Griffin.
Indeed, any phenomenon that accelerates virus mutations risks giving rise to variants that are more dangerous or, as Omicron was when it first appeared, significantly more transmissible than their predecessors.
In this context, should we stop prescribing molnupiravir? The authors of the study are careful not to comment, sticking to the field of genetics and referring the health authorities to their responsibilities.
And for some researchers, if these results remind us of the need not to prescribe molnupiravir all the time, we shouldn’t abandon it completely.
“Of course, you should not take molnupiravir systematically if you are infected” with the coronavirus, concludes infectious disease specialist Chris Butler of the SMC. “But in certain difficult cases, it is a medicine that can be very useful.”
Source: BFM TV
