China is forging ahead in the search for treatments for people sickened by the new coronavirus that has infected more than 28,000 people in a countrywide epidemic, killed more than 500 and seeded smaller outbreaks in 24 other nations.

The need is urgent: There are no approved treatments for illnesses caused by coronaviruses.

On Thursday, China began enrolling patients in a clinical trial of remdesivir, an antiviral medicine made by Gilead, the American pharmaceutical giant.

The drug has to be given intravenously, is experimental and not yet approved for any use, and has not been studied in patients with any coronavirus disease. But studies of infected mice and monkeys have suggested that remdesivir can fight coronaviruses.

And it appears to be safe. It was tested without ill effects in Ebola patients, although it did not work well against that virus, which is in a different family from coronaviruses.