Pfizer has said it is seeking full US approval for its oral Covid-19 antiviral treatment Paxlovid, which is currently available under an emergency use authorisation.

The company said it submitted a New Drug Application for Paxlovid to the Food and Drug Administration for the treatment of Covid-19 in vaccinated and unvaccinated people at high risk of progression to severe illness.

That is basically consistent with the drug's current EUA, which Pfizer said covers 50% to 60% of the US population, citing estimates from the US Centers for Disease Control and Prevention.

A full approval could mean the company would have the option to sell Paxlovid on the open market like other drugs, depending on whether or not the US government decides to stop buying the drug and providing it for free nationwide.

Also, "the company might have more control over educating the public with commercials, or however they want, to boost uptake," said Karen Andersen, healthcare strategist at Morningstar.

The two-drug treatment taken for five days beginning shortly after onset of Covid symptoms reduced the risk of hospitalisation or death by 88% in non-hospitalised, high-risk adult patients in Pfizer's clinical trial, which did not included vaccinated people.

Data from a study in Israel earlier this month showed Paxlovid reduced Covid-19 hospitalisation and death rates in vaccinated and unvaccinated patients 65 years and older, but was not found to prevent severe illness among younger adults.

More than 1.6 million courses of Paxlovid have been administered in the United States, according to data from the Department of Health and Human Services.