In a recent study revealed that Merck’s widely used antiviral Covid pill, molnupiravir, can potentially trigger mutations in the virus, with occasional transmission to other individuals. This development has raised questions about whether the drug might hasten the evolution of COVID-19.
Molnupiravir’s Mechanism of Action
Molnupiravir operates by introducing mutations into Covid’s genetic material, thereby weakening or eradicating the virus and reducing Covid levels within the body. However, a study published in the scientific journal Nature indicates that the virus can sometimes survive molnupiravir treatment, leading to mutated variants. And those can be spread to other patients.
Molnupiravir creates mutations because of its chemistry. Its structure is like that of a base of RNA, but can exist in two forms. One looks like a C and so binds to G, but it can then switch to another form that binds to A. This means it causes mainly G→A and C→T mutations pic.twitter.com/JPOKkV0rMy— Theo Sanderson (@theosanderson) September 25, 2023
Researchers from the United States and the United Kingdom conducted a comprehensive analysis of 15 million Covid genomes to identify mutations. And their occurrence timelines. Notably, they observed an increase in mutations in 2022 following the widespread use of molnupiravir in many countries.
However, It is important to note that there is no evidence suggesting that molnupiravir has led to the emergence of more transmissible or severe Covid variants, according to the study.
📄 📄 Our molnupiravir work is now out after peer-review! We definitively demonstrate that molnupiravir has resulted in viable SARS-CoV-2 viruses with significant numbers of mutations, in some cases with onwards transmission of mutated viruses. https://t.co/WFHedAHDfD— Theo Sanderson (@theosanderson) September 25, 2023
Response from Merck
Merck has responded to this new study, disputing the findings. A spokesperson for the company argues that the researchers assumed the mutations they analyzed associated with molnupiravir treated patients without conclusive evidence of transmission. They suggest that the study relies on circumstantial associations. And that genomes with the mutations were uncommon and linked to sporadic cases.
Merck had previously contested a similar study by the same research team in February, which proposed that molnupiravir might be contributing to new virus mutations in certain patients. At that time, Merck stated that they did not believe molnupiravir was likely to contribute to Covid mutations.
Amid Rising Covid Cases, Molnupiravir Usage Decreases
These findings come at a time when Covid is resurging in the United States, largely driven by newer virus strains. However, both the U.S. and other countries seem to be reducing their reliance on molnupiravir this year. Sales of the drug dropped to approximately $200 million during Merck’s third quarter, representing an 83% decrease from the more than $1 billion reported during the same period the previous year.
Merck’s molnupiravir has been a subject of controversy due to its potential to induce genetic mutations. The U.S. Food and Drug Administration initially approved the drug for emergency use in late 2021. It is not advisable to use Lagevrio during pregnancy due to concerns about potential harm to the baby. Additionally, molnupiravir is not authorized for use in patients under 18 because it may impact bone and cartilage growth.