Chinese renowned respiratory scientist Zhong Nanshan receives an interview with Xinhua in Guangzhou, south China's Guangdong Province, Jan. 28, 2020. (Xinhua/Liu Dawei)

Human-to-human transmissions have not stopped in Wuhan, Zhong Nanshan, the central government's top medical adviser, warned while epidemic-stricken Hubei Province faces a critical time in fighting the COVID-19 epidemic.

He noted that despite mounting efforts Wuhan authorities have put into the battle against the epidemic, two issues still have not been solved: to separate patients from healthy people, and to separate COVID-19 patients from flu patients.  

Zhong made the remarks at a press conference on Tuesday in Guangzhou, South China's Guangdong Province.  

Not only has the transmission of the novel coronavirus among human not stopped, but transmission of the common flu virus among people has worsened along with the growing number of patients with fever in Wuhan hospitals, according to Yang Zhanqiu, deputy director of the pathogen biology department at Wuhan University. 

Yang told the Global Times on Tuesday that many hospitals in Wuhan failed to check the pathogen for fever patients caused by other viruses, which has resulted in the spread of such viruses. Many such patients may have just caught flu. 

"The human-to-human transmission of flu worsened the human-to-human transmission situation of novel coronavirus in Wuhan," Yang said, as it has made screening for coronavirus patients more difficult.

Lack of medical resources at the early stage of the epidemic was also a reason for the worsening human-to-human transmission, according to a worker at a Wuhan community.

The worker told the Global Times on the condition of anonymity that many patients could only stay at home before being confirmed infected due to a shortage of medical materials at that time, increasing the risk of second-generation infection. 

Hubei has been tightening measures after the replacement of some senior provincial officials. However, some experts warned that these measures could not prevent potential infected people from the outset or prevent them from infecting others.  

Zhong called for urgent measures to deal with the two issues. 

Eighty percent of COVID-19 patients and 90 percent of the deaths are in Wuhan, Zhong said, noting that Wuhan is still the key to the battle against the epidemic, as the confirmed cases outside Hubei Province have been declining. 

Yang also urged Wuhan's hospitals to identify fever patients by their pathogens and separate them from patients of the novel coronavirus to lower the risks of transmission.

The worsened human-to-human transmission added to Wuhan's huge challenges, with large numbers of patients and high fatality, Yang said. 

As of 6:30 pm on Tuesday, there were 72,531 COVID-19 cases in China, 42,752 of which were in Wuhan. Among the 1,871 deaths nationwide,  1,381 were reported from Wuhan. 

A Wuhan resident blamed incomplete screening and late close-off management for human-to-human transmission. 

Some residential communities in Wuhan adopted seal-off management measures too late, a local resident surnamed Chen told the Global Times on Tuesday. 

"Our community only arranged the collective purchase of daily necessities today, after it was completely locked down. A few days ago, I heard that people went to the supermarket nearby, which led to a public gathering," she said. 

"Local authorities acted too slowly, missing the best opportunity to contain the virus spread," she added.

Qian Yuankun, deputy secretary-general of the Hubei provincial Party Committee, said at a press conference on Tuesday in Wuhan that problems of bungling treatment, late treatment and bed shortage in some places in the province led to the worsening of some patients' situation.  

Qian urged the speeding up of hospitalizing and treating patients. 

The Wuhan government announced it would build another 10 makeshift hospitals in the city with 11,465 beds.