In the battle against the coronavirus, few places seemed as confident of victory as China.
The country of 1.4 billion people had eradicated the virus so quickly that it was one of the first in the world to open up in spring last year. People removed their masks and gathered for pool parties. The government has swiftly stamped out fresh outbreaks by mobilizing thousands of people to test and trace infections.
That model is now looking increasingly fragile.
China is facing its biggest challenge since the virus first erupted in the Chinese city of Wuhan last year: The Delta variant is spreading through the country. Chinese officials have acknowledged that this outbreak will be much harder to curb than the others, because this variant spreads so quickly, often without symptoms.
New cases in cities such as Nanjing, Wuhan, Yangzhou and Zhangjiajie are showcasing the limitations of China’s zero-tolerance approach. They may also undermine the ruling Communist Party’s argument that its authoritarian style has been an unquestionable success in the pandemic.
Although the government had to stamp out a Delta flare-up in June in Guangdong Province, the spread has been far wider this time, with 483 cases since July 21, more than the total for the first five months of the year. By Tuesday afternoon, the virus had spread to 15 of the 31 provinces and autonomous regions in China.
“Once it reaches so many provinces, it’s very hard to mitigate,” said Chen Xi, an associate professor of public health at Yale. “I think this would be surprising and shocking to the rest of the world. Such a powerful government has been breached by Delta. This will be a very important lesson — we cannot let our guard down.”
Last week, Sun Chunlan, a vice premier of China, blamed “ideological laxity” for the Delta outbreaks and urged officials to step up their prevention efforts. “We cannot relax for a moment,” Ms. Sun said.
Some public health experts in the country say it is time for China to rethink its Covid strategy. In a recent essay, Zhang Wenhong, who advises the Chinese government on dealing with Covid-19, floated the idea of following a model similar to that of Israel and Britain, in which vaccination rates are high and the authorities are willing to live with infections.
For now, China has stuck to its strict playbook. Across the country, the government has instructed people not to travel unless necessary. In the cities of Zhangjiajie and Zhuzhou, 5.4 million people have been barred from leaving their homes. Roughly 13 million residents in the city of Zhengzhou, the site of deadly floods in July, had to stand in line for virus testing starting last weekend.
In Nanjing, where the first recent Delta cases appeared, millions of residents have endured four rounds of testing.
“It’s just torturing the masses,” said Jiang Ruoling, a Nanjing resident. Ms. Jiang, who works in real estate, said she understood the need for testing, but was still critical of officials for failing to control the latest outbreak. “The leaders are actually wasting resources and everyone’s time,” she said.
Yanzhong Huang, a senior fellow for global health at the Council on Foreign Relations, said China’s “containment-based” strategy would not work in the long run, particularly as new variants continue to emerge. “It will become extremely costly to sustain such an approach,” he said.