- Molnupiravir is administered to thousands of vulnerable patients to treat Covid
- Antiviral manufactured by American pharmaceutical giant Merck forces mutations in the virus
An anti-Covid drug hailed as revolutionary and prescribed to more than 20,000 British patients may actually cause the virus to mutate, scientists warned today.
Molnupiravir is being given to thousands of vulnerable Britons who test positive, such as patients battling cancer or liver and kidney disease.
The antiviral, made by US pharmaceutical giant Merck, protects against serious illness by causing mutations in the virus that fatally weaken it.
However, in some cases these mutations do not eliminate the virus, say researchers from the Francis Crick Institute and the UK Health Security Agency (UKHSA).
Instead, a patient can remain infected with a mutated version of Covid and transmit it to others, according to the team’s analysis of millions of virus sequences.
Molnupiravir demonstrated efficacy against the Omicron variant in laboratory studies
Experts have warned that it is now crucial to find out whether the mutations caused by molnupiravir make the virus more transmissible or severe, or allow it to evade immunity from previous infections or vaccines.
Some have even warned that its use could lead to the emergence of new variants, although the manufacturer has dismissed those fears.
Molnupiravir, sold under the brand name Lagevrio, works by stopping Covid from growing and spreading in an infected person, keeping virus levels low.
This helps the body’s immune system control the infection, reducing the risk of serious symptoms and hospitalization.
Clinical trials suggest the drug, which was distributed to patients in the UK from December 2021 and described as an “excellent addition” to the country’s “anti-Covid cupboard”, halves the risk of being admitted. or die from Covid.
The team, which included scientists from the University of Cambridge, Imperial College London, the University of Liverpool and the University of Cape Town, noted that molnupiravir’s effects are a result of it triggering a series of mutations in the virus. .
Many of the mutations damage or kill the virus.
However, in some patients, the virus is not completely cleared, meaning they can infect others with the molnupiravir-mutated virus.
They examined a family tree of 15 million Covid sequences, collected from global databases, to map their mutations over time.
Covid constantly mutates and most have little or no impact on the properties of the virus, such as its transmissibility or the severity of the infection it triggers.
However, in a study published in the journal Nature, researchers said they detected changes in the virus that looked very different from expected patterns.
These mutations were strongly linked to people who had taken molnupiravir.
The team observed that the frequency of these mutations increased in 2022, which is when the launch accelerated.
Unusual changes in the virus were also more common among older people, who are more likely to receive the drug, in countries known to have high use of molnupiravir, and among samples taken during clinical trials of the drug.
According to the researchers, three in 10 of the abnormal mutations observed in England occurred among those who received the drug.