An antiviral drug used around the world to treat Covid infections may have driven unusual mutations in the virus that have then gone on to spread, a study has found.
Molnupiravir was one of the first antivirals to be used against the coronavirus, in countries including the UK. It is designed to interfere with the way the virus reproduces by inducing catastrophic mutations. The idea was that doing so would prevent it from replicating.
When it was introduced there was concern that some of the mutations could, in rare instances, be beneficial to the virus and so lead to new variants of concern.
The research published in the journal Nature did not show that. It did appear to show, however, that there was clear evidence of occasions when the virus was still able to reproduce and even spread despite mutations caused by the drug.
The scientists trawled global databases of coronavirus sequences to find a particular signal. RNA, the genetic material used by the virus, is written in four letters: A, U, C and G. Molnupiravir was predicted to cause mutations that in particular switched G to A.
When they searched for these, they found that the mutations turned up far more frequently after the introduction of molnupiravir, in countries that used the drug, and in the at-risk people for whom the medicine was most often prescribed.
“Why this is important is this shows these things can be viable and transmissible, with 20 or more mutations,” Theo Sanderson, from the Francis Crick Institute in London, said. “The worry is that just occasionally such mutations could take the virus in a direction it wouldn’t otherwise, and it will be beneficial.” Sanderson said that he could not say to what extent that was a reasonable concern. “We’re not making a statement about the risks because that is very hard to do.”
Jonathan Ball, professor of molecular virology at Nottingham University, said that the findings were more information in the cost-benefit analysis of the drug, which has had mixed results in trials. He added that whether the mutations could change the way the virus behaved was “a key question”.
‘Give Covid jabs to everyone 50-plus’
Leading charities have said that Covid jabs should be offered to everyone aged 50 and above in order to boost uptake (Kat Lay writes).
National Voices, an umbrella organisation for charities including Macmillan Cancer Support, Marie Curie, Mind and Parkinson’s UK, made the call in a statement setting out “concerns surrounding the current Covid-19 and flu vaccine rollout”.
The winter vaccination programme began on September 11, and will see millions of Brits offered vaccination against the two viruses.
Unlike earlier programmes, those aged between 50 and 65 who do not have other vulnerabilities are not due to be given jabs.
The statement, signed by 61 charities, says that changing criteria between rollouts creates confusion for many of the people they represent.
They say: “It is clear that the ever-changing eligibility criteria for the vaccine is detrimental to people’s understanding of, and therefore uptake, of the vaccine. We are therefore calling on DHSC to create consistency between vaccine rollouts and clearly communicate such eligibility.
The move would “benefit individuals more affected by inequalities” who are more likely to experience health complications between 50 and 65, the charities said.
The statement also calls for better communication of the specialist advice underlying decisions on eligibility, and “a heightened approach to public health communications surrounding the rollout”.
The Department of Health and Social Care was approached for comment.
