A staff member handles nucleic acid testing samples at a novel coronavirus detection lab in Wuhan, central China's Hubei Province, Feb. 22, 2020.Photo:Xinhua

Some COVID-19 cases in Wuhan have shown unexpectedly long detoxification periods even after their symptoms disappeared, triggering public concerns about their infectivity; experts, however, noted that the infectiousness of these cases is limited and will not be discharged from the hospital until two successive negative test results are obtained.

Existing COVID-19 cases in Wuhan and Hubei, in general, have reduced to 23 as of Friday, according to the Chinese National Health Commission (NHC).

The number stood at 47 on Friday, of which, more than 30 are patients whose symptoms have disappeared but continue to test positive in the nucleic acid tests, Jiao Yahui, an official with the National Health Commission, told China Central Television (CCTV) late Friday. 

These patients no longer need treatment, clarified Jiao. But a visible concern still surged following the CCTV report among the public as social media users asked whether such people pose the risk of virus spread.     

"Continuous positive test results indicate that these patients are still expelling some virus," Yang Zhanqiu, deputy director of the Pathogen Biology Department at the Wuhan University, told the Global Times Saturday.

He added COVID-19 is a kind of acute infectious disease and that usually, patients of such conditions would only expel few viruses with limited infectiousness two weeks after the onset. 

Moreover, they would not be allowed to leave the hospital until two successive negative test results are obtained, Yang explained, citing the national discharge standard, in response to public concerns.

The downturn trend of active cases in Wuhan from Thursday to Friday also indicates that some of these patients have stopped expelling virus and tested negative in the COVID-19 nucleic acid test, experts noted.   

According to experts, patients continuing to expel virus three weeks after the onset are rare. But considering the total number of COVID-19 cases Wuhan has reported during the epidemic, it is reasonable to see some 30 such cases currently.   

Wuhan, the worst-affected Chinese city in the COVID-19 epidemic, has reported 50,333 cases in total as of Friday, according to NHC. 

The last critical COVID-19 patient in Wuhan tested negative in the nucleic acid test on Friday. 

The remaining patients in Wuhan include some ordinary patients or those with mild symptoms, who will continue to receive treatment, as well as those who do not need treatment but are yet to test negative.

Overall, the medical treatment on COVID-19 patients in Wuhan has achieved a significant victory, said Jiao.