The maker of an anti-coronavirus pill in Japan says clinical testing has shown that the risk of developing symptoms associated with "long COVID" almost halved with use of the drug.
Japanese pharmaceutical company Shionogi released the results from the final phase of a trial of the antiviral at a conference in the United States on Wednesday.
The drug ensitrelvir, known as Xocova in Japan, is said to shorten the recovery period from COVID-19 symptoms, including fever, by one day.
Xocova was given emergency authorization in the country in November as the first oral drug that can be used for patients as young as age 12 who have a low risk of developing severe symptoms.
Shionogi said over 1,800 people took part in the trial.
One group with specific COVID-19 symptoms took Xocova. Six months later, 14.5 percent of them reported having at least one of 14 long-term symptoms, including cough, sore throat, low energy and taste disorders.
As for the placebo group, 26.3 percent of members reported such symptoms.
The company says the results show use of the drug brought a 45-percent relative risk reduction.
It says the trial also shows a 33-percent risk reduction in the development of neurological symptoms, such as difficulty with concentration and thinking, memory loss and insomnia.
Shionogi says a follow-up of the trial will continue for a one-year period to further confirm the effects. It says it is aiming to obtain additional approval that would allow the drug to be used to prevent long-term symptoms, depending on further trial results.