Faster action

Zhong Nanshan, a prominent respiratory expert and an academician in the Chinese Academy of Engineering, said in a lecture on Friday that some countries have decided to coexist with the virus due to Omicron's relatively milder symptoms and lower fatality rate, but the strain can lead to many deaths if anti-virus restrictions are entirely lifted in China.

"Completely opening up does not fit China's situation," he said. "In China, we should stick to the dynamic zero-COVID strategy and ease policies gradually in the future."

On Sunday, Liang also stressed that for now the full implementation of the dynamic zero-COVID strategy will still bring the best outcomes at the lowest cost.

He made clear that at the center of the dynamic zero-COVID strategy is rapidly detecting new infections and blocking the virus' transmission to prevent its continued spread in communities.

The approach does not try to prevent new cases from occurring at all or maintain zero tolerance for new outbreaks, he said. "We're unable to ensure that no infections occur because the virus can spread stealthily. But we must swiftly detect and handle new clusters."

To get past the peak of the outbreak in Shanghai will require all-out efforts, such as multiple rounds of mass screening and lockdowns, to cut the virus' spread across the population, Liang said.

"The Omicron strain spreads so quickly that we must roll out measures at an even faster pace than our fight against previous mutations such as Delta and Alpha," he said.

In addition, the high infectiousness of Omicron means that letting a few cases slip away could soon result in exponential rises and larger clusters.

So far, Shanghai has managed to avert the kind of exponential increase that the Omicron strain is capable of triggering with its ferocious speed of transmission, suggesting that the current measures are playing an important role in containing the epidemic, according to Liang.

However, "the fight in Shanghai is at its most acute and tense phase, and we must keep pressing on", he said.