SHANGHAI — Chinese authorities extended the lockdown of Shanghai to cover all of the financial center’s 26 million people on Tuesday, after city-wide testing saw new coronavirus disease 2019 (COVID-19) cases surge to more than 13,000 amid growing public anger over quarantine rules.

The lockdown now covers the entire city after restrictions in the city’s western districts were extended until further notice, in what has become a major test for China’s zero-tolerance strategy to eliminate the novel coronavirus.

At least 38,000 personnel have been deployed to Shanghai from other regions in what state media has described as the biggest nationwide medical operation since the shutdown of Wuhan in early 2020 after the first known coronavirus outbreak.

The city’s quarantine policy has been criticized for separating children from parents and putting asymptomatic cases among those with symptoms. Some public health experts say it is no longer an effective strategy.

“I do not think this is a good idea as more than 24 months into the pandemic we know so much more,” said Jaya Dantas, professor of international health at Curtin University in Australia, adding that China’s “resource intensive” strategies to combat COVID-19 needed to be revised.

Members of the public shared videos across social media expressing concern about the lockdown.

Sun Chunlan, China’s vice-premier in charge of COVID prevention, urged grassroots Party organizations to “do everything possible” to help residents solve their problems, such as ensuring access to medicine, food and water.

Thousands of Shanghai residents have been locked up in rudimentary “central quarantine” facilities after testing positive, whether they are symptomatic or not.

Jane Polubotko, a Ukrainian marketing manager now held in the city’s biggest quarantine center, told Reuters it was unclear when they would be released.

“Nobody knows how many tests we need to get out,” she said.

In an interview with Communist Party newspaper People’s Daily on Saturday, Chen Erzhen, a doctor in charge of one Shanghai quarantine facility, said it was possible that China would revise guidelines and allow asymptomatic patients to stay home, especially if the number of cases continued to mount.

“The most important thing is the problem of personal compliance,” he said.

Shanghai imposed tough restrictions last week as authorities struggled to contain what has become the city’s biggest COVID-19 outbreak, after originally taking a more piecemeal approach.

“Currently, Shanghai’s epidemic prevention and control is at the most difficult and most critical stage,” said Wu Qianyu, an official with the municipal health commission, at a Tuesday briefing. “We must adhere to the general policy of dynamic clearance without hesitation, without wavering.”

Shanghai reported a record 13,086 new asymptomatic coronavirus cases on April 4, authorities said on their WeChat channel, up from 8,581 the previous day, after a city-wide testing program swabbed more than 25 million people in 24 hours.

The government said it had collected 25.7 million samples in 2.4 million test tubes on Monday, and almost 80% of the total had been tested by Tuesday morning. Any positive results are followed up at the individual level.

The proportion of asymptomatic cases is far higher in Shanghai than the rest of the world, which has been attributed to a screening process that catches infected people before they become ill. However, experts said it did not explain why symptomatic cases fell on Monday to 268, from 425 a day earlier.

Analysts outside China warn about the economic costs of the campaign to curb infections.

“What is most striking in Shanghai is the difficulty that the authorities are having in managing logistics, particularly conditions in centralized quarantine facilities,” said Michael Hirson, China analyst with the Eurasia Group consultancy.

“Given that Shanghai has a highly capable government, current problems pose a warning for local governments across China where capacity is not as high and major outbreaks could stretch resources further to the limits.” — Reuters