Could anti-viral drug make evolution of COVID worse?

An approved COVID drug has come under question, with scientists saying that it could in fact help the virus evolve. Designed to mutate viruses out of existence, there are fears the anti-viral drug – molnupiravir – could do the opposite for COVID.

In a new article in Nature, a group of scientists outlined how COVID could ‘escape’ the drug. The predominantly UK-based researchers identified molnupiravir, sold commercially as ‘Lagevrio’, as a potential weakness in the suite of COVID treatments.

This does not mean that those who have used molnupiravir face any risks, but it could affect future COVID patients.

Who uses molnupiravir and how can it make COVID worse?

Molnupiravir is the result of its own evolutionary process. It is the descendant of a drug used to treat a virus that affects horses. When that drug, ‘EIDD-1931’, was converted into a ‘prodrug’ called ‘EIDD-2801’, it showed effectiveness against a number of human viruses. These include Ebola and various coronaviruses. EIDD-2801 is in fact molnupiravir.

Having been approved for clinical trials in the US in 2019, molnupiravir was identified as a potential COVID treatment in 2020. Trial results proved promising, and molnupiravir was approved for public use.

By 2022, molnupiravir was Australia’s most widely dispensed oral antiviral drug for the treatment of vulnerable patients with COVID. But late last year, the National COVID-19 Clinical Evidence Taskforce advised against its routine use.

Following analysis that showed the drug did not reduce hospital admissions or deaths among higher risk, vaccinated adults with COVID, attitudes changed. This analysis basically found the opposite of what the previous American trials had shown.

Acknowledging that molnupiravir did seem to prompt a faster recovery time and reduced viral load, the taskforce ‘downgraded’ the drug. In December last year, it updated the drug’s listing with a stated recommendation: “Do not routinely use molnupiravir for the treatment of COVID-19.”

Professor Mark Morgan, a member of the Taskforce’s guidelines leadership group, was more blunt in his assessment. “In summary, molnupiravir did not work,” he told newsGP.

For those who have been prescribed molnupiravir, this does not present any risk. It merely means the drug is not likely to have played a part in their COVID recovery. But the fact that it was ineffective means it was more likely that molnupiravir would evolve and spread, rather than “mutate out of existence”.

The future as a COVID treatment

The Australian taskforce’s recommendation, followed by the newly-published research, is not a ‘nail in the coffin’ for molnupiravir. According to some experts, the drug still has a place in the treatment of COVID.

Stephen Griffin, professor of cancer virology at the University of Leeds, summed up a common view. He asked: “Does this mean we should stop using molnupiravir?” Answering that question, Prof Griffin said new evidence prompts a rethink about the use of molnupiravir on its own.

“But it shouldn’t be discarded and could still be valuable if we were to use it in drug combinations,” he said.

Have you been prescribed molnupiravir as a COVID treatment? Do you feel it was effective in any way? Let us know via the comments section below.

Also read: Long COVID response falls short in Australia

Health disclaimer: This article contains general information about health issues and is not advice. For health advice, consult your medical practitioner.

Andrew Gigacz
Andrew Gigacz
Andrew has developed knowledge of the retirement landscape, including retirement income and government entitlements, as well as issues affecting older Australians moving into or living in retirement. He's an accomplished writer with a passion for health and human stories.


  1. Take this as a reminder to the medical profession and the pharmaceutical industry that what is often promised isn’t always what is delivered. There have been many drugs used over the years that have had unpleasant and often tragic side effects that have not been evident until lives have been changed and lost before a causal link was identified.
    Too many times it has been the placebo effect ahead of real medical benefit.

  2. My wife was prescribed this drug and whether coincidentally or due to a placebo effect she thankfully recovered pretty quickly. However, if this drug does in fact deliver no more than a sugar pill effect it was one of the biggest conns of the Covid event and there were a few to choose from. While this drug cost us $30 on the PBS, the non-PBS price shown on the container is $1,101.39. And we wonder where our medical budget goes?

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