Despite experts raising doubts over the plasma therapy to treat Covid-19, the US Food and Drug Administration (FDA) has issued an emergency use authorisation (EUA) for convalescent plasma to treat the deadly respiratory disease.

In a statement on Sunday, the FDA said that "known and potential benefits of the product outweigh the known and potential risks of the product".

According to a news report, the FDA said more than 70,000 patients had been treated with convalescent plasma.

At a White House briefing on Sunday, President Donald Trump said: "Today, I am pleased to make a truly historic announcement in our battle against the `China virus` that will save countless lives."

"Today`s action will dramatically increase access to this treatment," the President said, adding that he has directed the FDA to approve the EUA for convalescent plasma therapy.