GUANGZHOU, Feb. 27 (Xinhua) -- The novel coronavirus has a prominent feature whereby patients have a large amount of very sticky mucus in their small airways, said renowned Chinese respiratory specialist Zhong Nanshan at a press conference in Guangzhou on Thursday.
Obstruction of the airway can lead to secondary infections, said Zhong. "We are working to solve the problem," he said.
The mortality rate among critically ill patients in Wuhan, the epicenter of the outbreak, is close to 60 percent, Zhong said, adding that experts are searching for solutions to hypoxia, and some new methods have proved effective in relieving breathing difficulties of patients in Wuhan.
Addressing the question that some patients discharged from hospital after initial recovery have tested positive for the coronavirus for a second time, Zhong said COVID-19 is a new infectious disease, the process of which is not known yet.
"We can't draw an absolute conclusion at present and have to follow its development closely. But according to the laws of microorganisms, those with enough antibodies will not be infected again," Zhong said.