The Covid pill: new antiviral taskforce faces tough challenge

A new taskforce is to lead the UK’s search for a home antiviral treatment such as a pill or capsule that can help prevent Covid-19 patients from becoming seriously ill.

Announcing the plan at a Downing Street press briefing yesterday, Boris Johnson said he hoped a “Covid pill” would be available by the autumn to help combat any third wave of the virus.

But, as The Times says, developing antiviral treatments has so far “proved difficult”.

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‘A lot of work’

Nat Moorman, a virologist at the University of North Carolina at Chapel Hill, told Nature last week that “a lot of work” needs to be done to find an antiviral treatment for the coronavirus. The journal reports that despite previous outbreaks of Sars and Mers, there have been “practically no strong antiviral drug candidates to quickly test and deploy against Sars-CoV-2”, the virus that causes Covid-19.

The candidates that have been considered include remdesivir, originally developed to treat hepatitis C and Ebola. But Nature says that “some clinical studies have failed to confirm that it offers [Covid] patients any benefit. And the drug is expensive, difficult to manufacture and must be given intravenously in a hospital - all undesirable attributes in the middle of a pandemic.”

Experts are hoping that some of those issues might be avoided with another antiviral drug, molnupiravir, which is undergoing early-stage testing in hamsters by the US National Institutes of Health (NIH) and late-stage human trials by biotech company Ridgeback Biotherapeutics and pharmaceutical Merck. Meanwhile, the NHS is testing an antiviral called favipiravir in trials involving UK patients.

Targeting the problem

Developing antiviral treatments is hard is “because viruses offer far fewer targets than bacteria to attack”, says The Times.

While bacteria are whole living cells, “viral pathogens live inside our own cells and depend on our proteins for most of their needs”, explains Scientific American. There are also few natural antivirals, “so scientists have to invent them from scratch”, the science magazine continues.

The challenge for antiviral designers is “to stop the virus without damaging the inner workings of healthy cells too”.

The good news

Johnson said yesterday that he hopes that at least two effective treatments will be developed to provide “another vital defence against any future increase in infections”. The aim is to have an antiviral pill or capsule that can be taken at home by people who have tested positive for Covid or has been exposed to the virus.

Patrick Vallance, the government's chief scientific adviser, pointed to the speed at which the vaccines and other treatments such as the steroid dexamethasone were found and rolled out. “The taskforce will help ensure the most promising antivirals are available for deployment as quickly as possible,” he said.