China has relied on such curbs on movement and mass testing to keep case numbers low but, the latest outbreak raises questions about whether China can continue to avoid living with the virus.

But Lei reaffirmed the country’s commitment to its playbook, saying the present outbreak required a stricter, earlier and quicker response.

“The general strategy to prevent imported cases and internal rebounds and the general policy of dynamic zero-Covid are fully effective in dealing with the Omicron outbreak,” he told state broadcaster CCTV.

03:46

No respite for Covid cases in Hong Kong as infections surge in mainland China

No respite for Covid cases in Hong Kong as infections surge in mainland China

The NHC reported 2,125 new cases across 19 provincial areas, marking a fourfold rise from a week ago but down from 3,122 a day earlier.

The total comprised 1,337 symptomatic and 788 asymptomatic infections. Unlike most other countries, China only classifies cases with symptoms as confirmed.

“Throughout February, my country had low-level sporadic spread nationwide, but it was well controlled, with fewer than 200 total cases [daily],” he said on his Weibo social media account.

“But … it took only 11 days to go from 119 daily cases on March 1 to 3,122 cases on March 12. And this happened under strict nationwide active surveillance and prevention of the coronavirus.”

WHO discussing conditions to declare end of Covid-19 emergency

The NHC reported 169 new local cases in Shanghai, 128 of them asymptomatic, pushing the number of cases so far this month to nearly 500.

Unlike the rest of China, Shanghai has adopted a more flexible epidemic control model that relies on quick and precise contact-tracing to avoid a lockdown.

But authorities have ordered travellers in and out of the city to present a negative nucleic acid test result from within the previous 48 hours, and suspended more than 700 bus routes with other provinces.

Localised lockdowns and mass testing were already under way in the city after Covid-19 broke out earlier in March.

02:15

China sees biggest Covid-19 surge in 2 years, steps up measures

China sees biggest Covid-19 surge in 2 years, steps up measures

Jin Dong-Yan, a professor at the University of Hong Kong’s faculty of medicine, said lockdowns and universal testing would reduce cases but not eliminate the coronavirus.

“It worked when the number of cases were small and also when they were dealing with the Alpha and Delta variants, [which are] less transmissible,” said Jin, a molecular virologist.

“But for Omicron, for BA. 2, it’s highly transmissible and many of the approaches might not work or might not work as they expect.”

Jin said China should instead focus on developing surveillance techniques, such as regularly selecting 10,000 random people with fever from different areas of a city and testing them for the coronavirus.

The size of China and its many underdeveloped areas meant it would be difficult to detect asymptomatic cases of Covid-19.

Some Shenzhen residents point finger at Hong Kong over Covid-19 lockdown

“For example in Jilin [province], it was detected very late,” he said.

“It had already spread to many different places before they detected the first case. So the first case was not the first case. It may be the 1,000th or 10,000th case because it has already spread.”

Jilin, a province in northeastern China, is the epicentre of this wave, and reported 1,026 new cases, a drop from the 2,156 cases a day earlier.

Over half the province’s cases were from Jilin City and most of the rest reported in the capital Changchun.

And the cases were growing quickly. After the NHC announced its daily case tally on Monday, the Jilin provincial epidemic control unit said another 3,868 preliminarily positive cases had been detected.

“These people were tested preliminary positive in mass nucleic acid testing in the recent outbreak and require clinical diagnosis,” Jilin provincial health commission deputy director Zhang Yan said.

In a sign of Beijing’s concern about the outbreak, Vice-Premier Sun Chunlan arrived in the province on Sunday to lead anti-epidemic measures.

“Rapid antigen testing is being encouraged because results from nucleic acid testing take longer,” Leung Chi-chiu, a Hong Kong-based respiratory medicine specialist, said.

Antigen tests directly detect the proteins that stimulate a person’s immune response, while nucleic acid tests detect the RNA genetic material of the virus. Although antigen tests return a result within minutes, they are generally less sensitive and more likely to return a false negative result.

While there has been debate about whether China can keep trying to contain the coronavirus, Leung said the recent spike would not trigger a policy shift towards “living with Covid-19”.

“When to start ‘living with Covid’ depends on whether there will be renewed vaccines that could handle the new variants … and affordable medication to reduce the effects caused by the virus,” he said.

Leung said the lack of widespread outbreaks in China compared to countries that were living with Covid-19 meant the Chinese population lacked the natural immunity needed to minimise the impact once pandemic control measures were abandoned.

Foxconn suspends iPhone factories in Shenzhen amid lockdown of tech hub

In the countdown to the restrictions in Shenzhen, residents queued up in supermarkets and raced to grab essential office equipment to prepare for at least a week of working from home.

Taiwanese tech giant Foxconn said its plant in Shenzhen, which makes Apple products and their components, had stopped operating and would reopen at a date determined by the local government.

In Hong Kong, which neighbours Shenzhen, Chief Executive Carrie Lam Cheng Yuet-ngor said supplies, such as food and necessities, to Hong Kong would continue.

Shenzhen accounted for all but four of the 79 new local symptomatic cases found in Guangdong province. However, Guangdong’s overall case count was bolstered by the city of Dongguan, which contributed 140 of the 151 daily asymptomatic cases in the province.