Zhong Nanshan (Photo: People's Daily app)

Herd immunity isn't reliable in disease prevention and control of COVID-19 as no existing evidence proves that immunity against the novel coronavirus lasts a lifetime. So the most daunting task right now is the research and development of vaccines, China's top COVID-19 expert Zhong Nanshan said at a press briefing in Guangzhou on Wednesday.

Zhong suggested countries around the world should take more active measures to tackle the pandemic. Prevention and control measures should be put in place. Not only patients with symptoms but also their close contacts without symptoms should be examined closely, and once confirmed infected, they should be isolated and quarantined in a timely manner, he said.

China's measures on preventing and controlling the coronavirus are appliable to other countries, said Zhong.

China has been greatly determined to control the virus, even at the price of economic losses, which might be different from the perspective of other countries, Zhong added. 

For the Chinese government, the health and lives of its people are of top priority, Zhong said, noting that the current task for China is to prevent imported infections and resume production, where a balance is needed.

(Compiled by Han Xiaomeng & Shan Xin)