The number of confirmed COVID-19 cases soared by more than 5,000 in one day, officials in China said Friday — as they announced that more than 1,700 medical workers have been infected by the deadly bug.

Cases in mainland China rose to 63,851 by the end of Thursday — up 5,090 from the day before — as the death toll reached 1,380, up by 121, the country’s National Health Commission said.

But the thousands of new reported cases don’t necessarily represent a sudden surge in new infections — as much as they reflect a new methodology adapted by officials in Hubei province, the epicenter of the outbreak.

The province is now including cases based on a physician’s diagnosis before they are officially confirmed by lab tests. Out of the 5,090 new cases, 3,095 were diagnosed in this manner.

Officials say they are hopeful the new method can help identify suspected cases so they can be treated more quickly — though it also reflects the surge of people seeking treatment and the growing backlog of untested samples in Hubei and its capital, Wuhan.

Meanwhile, National Health Commission Vice Minister Zeng Yixin confirmed Friday that 1,716 of the country’s health workers have been infected by the coronavirus and six of them have died.

More than 87 percent of those workers are based in Hubei, he said.

“At present, the duties of medical workers at the front are indeed extremely heavy,” Zeng told reporters at a news conference. “Their working and resting circumstances are limited, the psychological pressures are great, and the risk of infection is high.”

More analysis still needs to be done to determine how many were infected in hospitals, according to Zeng.

The announcement comes as Chinese officials and hospitals have spoken out about a shortage of protective equipment, including face masks.

The death of Dr. Li Wenliang, one of the first whistleblowers on the spread of coronavirus in Wuhan, sent shockwaves through Chinese social media as many criticized the country’s Communist government for denouncing his efforts to sound the alarm.

With Post wires