Top expert clarifies facts on coronavirus

Zhong Nanshan, a prominent Chinese epidemiologist, said at a news conference in Guangzhou, Guangdong province, on Wednesday that there is no evidence proving that Wuhan is the source of the coronavirus that causes COVID-19 pneumonia. It's not responsible to jump to such a conclusion before figuring it out, he said.

Zhong added that there is also no evidence that a person becomes immune forever to coronavirus-related illnesses after having been infected once. The next key task is to produce an effective vaccine, which needs international cooperation, he said.