The Food and Drug Administration (FDA) plans to authorise the emergency use of remdesivir to treat those infected with the coronavirus.

The experimental antiviral drug is being tested on patients as a treatment for Covid-19.

Both Dr Anthony Fauci and President Donald Trump have expressed optimism about early results from the trials, which show that it shortens recovery time for some patients suffering from the virus. Dr Fauci described the trial results as “very optimistic.”

Dr Fauci, who oversees the National Institute of Allergy and Infectious Diseases (NIAID), cautions that results of their study need to be peer reviewed, but remains positive on the implications of the trial, as remdesivir appears to shorten recovery time by just under a third.

Manufactured by Gilead Sciences, the drug was developed to fight Ebola, but a clinical trial failed to yield results necessary for approval as a treatment.

Gilead’s own study using the drug to treat Covid-19 looked at 397 patients with severe infections taking the drug over five and 10-day courses and found that more than half were discharged from hospital within 14 days.

The company said on Wednesday it was “aware of positive data emerging” in the NIAID study overseen by Dr Fauci, that “met its main goal.”

Dr Fauci said: “Although a 31 per cent improvement doesn’t seem like a knockout 100 per cent, it is a very important proof of concept because what it has proven is that a drug can block this virus.”

A third study that was conducted in China was less positive as it questioned the efficacy of the treatment on severely ill patients. That study was incomplete as it lacked enough participants.

Further details are expected in an upcoming briefing later on Wednesday.