An antiviral drug that is given to people recently infected with Covid is now set to be trialled in hospitalised patients.
Clinical studies have suggested the drug, which is made by Pfizer and known as Paxlovid, can cut the risk of hospital admission or death by 88 per cent if given in the first five days of symptoms.
Having already been approved in the UK for the early-stage treatment of Covid, scientists will now assess how Paxlovid performs when administered to people hospitalised with the infection.
The world's largest randomised study of potential medicines for Covid-19, dubbed the Recovery trial, will roll out the drug in hospitals across Britain.
"Paxlovid is a promising oral antiviral drug but we don't know if it can improve survival of patients with severe Covid-19," said Peter Horby, a professor at the University of Oxford and joint chief investigator of the Recovery trial.
Scientists said they aim to mainly find whether Paxlovid reduces the risk of death among patients admitted to hospitals with Covid-19.
The study, led by the University of Oxford, will also probe whether the treatment shortens the length of hospital stay or reduces the need for a mechanical ventilator, they added.
The Pfizer treatment is part of a class of drugs called protease inhibitors, currently used to treat HIV, hepatitis C and other viruses, and works by stopping the virus from replicating.
This keeps virus levels in the body low and allows the immune system to overcome the infection.
The two active substances of Paxlovid come as separate tablets that are packaged together and taken together, twice a day by mouth for five days.
