The Huanan Seafood Market in Wuhan, where it is believed the outbreak started. Photo: Weibo

China has shaken up its Covid-19 testing system to include asymptomatic coronavirus carriers.

The National Health Commission will now include cases of people infected by the new strain of virus, but show no symptoms, in its daily updates.

State-run Xinhua news agency reported the development after it was announced at a central government Covid-19 prevention meeting on Monday, which was chaired Premier Li Keqiang.

“The group stressed the control of cases of infections that show no symptoms,” the official mouthpiece of the ruling Communist Party said.

On Monday, the National Health Commission revealed there were 1,541 asymptomatic carriers under medical observation on mainland China, including 205 imported cases, according to a report in the South China Morning Post.

“Classified Chinese government data suggested the proportion of silent carriers could be as high as one-third of those who test positive,” the Post stated.

Latest research, meanwhile, has showed that middle-aged people, and not only the elderly, have a dramatically higher risk of dying or developing serious illness from Covid-19.

Released on Tuesday, the findings by British-based researchers came in a new comprehensive analysis of virus cases in mainland China.

More than 3,600 confirmed cases were analyzed, as well as data from hundreds of people repatriated from the outbreak city of Wuhan. 

They found that age was a key determining factor in serious infections, with nearly one in five over-80s requiring hospitalization, compared to about 1% among people under 30.

Taking into account estimates of the number of cases that may not have been clinically confirmed – that is, mild or asymptomatic infections – the data showed the hospitalization rate of patients in their 50s was 8.2%. 

The study, published in The Lancet Infectious Diseases journal, estimated that the mortality rate from confirmed virus cases in mainland China was 1.38%. 

If unconfirmed cases were taken into account, the death rate dropped to 0.66%.

“Our estimates can be applied to any country to inform decisions around the best containment policies for Covid-19,” Azra Ghani, a study co-author from Imperial College London, said.

“There might be outlying cases that get a lot of media attention, but our analysis very clearly shows that at aged 50 and over, hospitalization is much more likely than in those under 50, and a greater proportion of cases are likely to be fatal,” she added. 

– additional reporting AFP