The number is far higher than that recorded during the 2003 severe acute respiratory syndrome (Sars) epidemic, although there have been 12 times more confirmed cases of Covid-19.

Zeng Yixin, deputy director of the National Health Commission, told a press conference on Friday that the infected medical workers accounted for 3.8 per cent of the total number of Covid-19 cases in mainland China, with 1,502 being from Hubei, 1,102 of whom were from Wuhan city.

Six medical workers had died from the disease as of Tuesday, Zeng said.

Earlier this week the South China Morning Post reported that there had been at least 500 confirmed and 600 suspected Covid-19 cases among health care workers. Medical staff also said that they had been banned from releasing the figures.

Coronavirus infects 1,716 medical staff as China reports 5,090 new cases

Many health care workers were infected in January when the authorities still insisted there had been few cases of human-to-human transmission, and many others worked without proper protective clothing due to shortages.

In May 2003, towards the end of the Sars outbreak, the authorities said 963 medical workers had been infected out of a total of 5,309 confirmed cases.

The number of Sars cases on mainland China eventually rose to 5,237, 349 of whom died.

In Hong Kong 386 health care workers were infected by Sars, including eight fatalities. In total the city recorded 1,755 infections and 299 deaths.

Middle East respiratory syndrome (Mers) also infected 415 medical workers out of a total of 2,223 confirmed cases between September 2012 and June 2018, according to a paper published in the Journal of Infection and Public Health last year by researchers from the World Health Organisation and two other institutes.

Cai Haodong, a communicable diseases specialist from Beijing’s Ditan Hospital, said the absolute number of health care worker infections was far higher than during the Sars epidemic because there were many patients who had not initially shown any symptoms.

“The enemy (coronavirus) is in the dark. The awareness of doctors of non-communicable disease was not strong. They may have lowered their guard when the patient did not show any symptoms.”

Health care workers were also forced to go to the frontline without proper protective clothing and masks, she added.

“The doctors in Wuhan don’t have sufficient protective gear and they are forced to go to the frontline. The price is just too high,” she said.

The large number of health care worker infections increases the risks of cross-infection in hospitals.

“When doctors are infected, they may infect patients and cause cross-infections. That is why the United States requires doctors to have influenza vaccines so that they won’t pass it on to patients,” Cao said.

Chinese military sends in fresh medical crews to coronavirus-hit Wuhan

“Having over 1,500 infections among health workers is a large number, Professor Joseph Lau Tak-fai of the JC School of Public Health and Primary Care of Chinese University of Hong Kong.

He said in the early stage of outbreak, many patients might not show symptoms and doctors may not be aware they were contagious.

“In the second stage, even though health care workers were aware of the human-to-human transmission they may still have (had) to go to the frontline, even without enough protective gear.”

Lau said the risk to medical staff was exacerbated by the strain on the medical system but said Hong Kong was unlikely to see a repeat of the Wuhan situation or the Sars outbreak because it is better prepared and has not seen as many Covid-19 cases.

The World Health Organisation admitted that in-hospital infection was a concern, saying: “It is vitally important in health care settings, that health care workers are able to protect themselves from infection. Hospital acquired infections are a concern for all countries responding to Covid-19.”

The scale of cross-infections caused by the health care worker infections in hospitals remains unknown.

Huang Chaolin, the vice-director of Wuhan Jinyintan Hospital, who published a paper in The Lancet on the clinical symptoms of Covid-19, started to show symptoms of the disease on January 17 and had it confirmed five days later.

At least 500 Wuhan medical staff infected with coronavirus

Huang told China Newsweek that he now believes he had been infected by two patients who showed no symptoms when he met them on January 10.

He initially thought he just had a cold and carried on working at the hospital, even hosting visiting specialists from Beijing and holding a press conference on January 19.

The central government has been trying to boost frontline medical workers’ morale by portraying them as heroes and offering them cash and other rewards.

These efforts redoubled after the death of Li Wenliang, who was reprimanded by police after warning his colleagues about the new disease.

His death last whipped up a national storm of outrage about the initial cover-up.