Anti-Covid drug may have led to virus mutations — study

PARIS, France — An anti-Covid drug widely used across the world may have caused mutations in the virus, researchers said on Monday, but there was no evidence that the changes had led to more dangerous variants.

Pharmaceutical giant Merck's antiviral pill molnupiravir was one of the earliest treatments rolled out during the pandemic to prevent Covid becoming more severe in vulnerable people.

The drug, which is taken orally over a five-day course, works mainly by creating mutations in the virus with the goal of weakening and killing it.

However, a new UK-led study has shown that molnupiravir "can give rise to significantly mutated viruses which remain viable," lead author Theo Sanderson told AFP.

Sanderson, a geneticist at London's Francis Crick Institute, emphasised that there is no evidence that "molnupiravir has to date created more transmissible or more virulent viruses."

None of the variants that have swept the world were due to the drug, he added.

But "it is very difficult to predict whether molnupiravir treatment could potentially lead to a new widely circulating variant which people don't have prior immunity to," he added.

Mutational signature

For the study, which was published in the journal Nature, the researchers sifted through databases of more than 15 million genome sequences of SARS-CoV-2, the virus that causes the Covid disease.

The researchers used this data to track changes in how the virus mutated during the pandemic, finding signs of a particular "mutational signature" in patients they believe is linked to molnupiravir.

In 2022, as the drug was prescribed in huge numbers, there was a significant increase in patients who had this mutational signature, the study found.

This signature was more commonly