BEIJING — Two of China’s largest cities, Shenzhen and Shanghai, imposed stringent restrictions on Sunday on the movements of their residents, as a coronavirus outbreak continued to spread in the metropolis and across much of mainland China.
While China still has far fewer coronavirus cases than most countries, the daily count of known infections has accelerated rapidly. The country’s National Health Commission reported 3,122 new cases on Sunday, up from 1,524 on Saturday and 1,100 on Friday, and a couple hundred per day a little more than a week ago. The average number of new cases has reached 1,370 per day over the past week, according to the Center for Systems Science and Engineering at Johns Hopkins University.
Shenzhen, a city bordering Hong Kong that is the hub of China’s tech sector and electronics manufacturing industries, announced on Sunday night a lockdown for the next seven days. All nonessential workers must stay home, adults must undergo three P.C.R. tests in the coming days for the coronavirus and buses and subway trains are being halted. Supermarkets, farmers’ markets, pharmacies, medical institutions and express delivery services will be allowed to stay open.
A lockdown in Shenzhen might further disrupting global supply chains, because Shenzhen has one of the world’s largest ports. An outbreak in Shenzhen in late spring of last year held up port operations and caused a steep spike in global shipping rates that helped drive up prices for imported goods in the United States and elsewhere.
China has tried to keep ports running during outbreaks since then by requiring many port workers to live at the docks for weeks at a time. The municipal lockdown order on Sunday evening did not specifically exempt port workers, but port management companies have argued in the past that their workers are essential.
Shenzhen and Shanghai both barred their residents over their weekend from leaving either city unless clearly necessary, and even then only with a negative result from a P.C.R. test. Shanghai also halted intercity bus service, but has not ordered a citywide lockdown.
Shenzhen reported 66 cases on Sunday, all but six of them with symptoms already apparent. By comparison, Shanghai reported 65 cases on Sunday, but just one of the infected already showed symptoms. All infected people are immediately hospitalized in China, sometimes in makeshift hospitals that are quickly erected, so as to isolate them and limit further spread of disease.
Shenzhen had tightened Covid-19 prevention and control measures in February, including steps to prevent truck drivers from bringing infections into mainland China from Hong Kong. Despite those efforts, many users of Weibo, the Chinese social media network, faulted Hong Kong for the recent outbreak in Shenzhen, because the city has not implemented the kind of lockdown measures seen in mainland China, despite now having tens of thousands of new cases each day. Beijing reported seven cases on Sunday, only one of which was asymptomatic.
Shanghai Disneyland announced that effective Sunday, it was halting all theater shows and requiring any visitors to show negative results from a P.C.R. acid test taken in the preceding 24 hours.
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The most severe outbreaks in mainland China right now are in towns and cities in the northeastern province of Jilin, which borders North Korea and Russia accounted for two-thirds of the cases announced on Sunday. Two mayors were dismissed in the province on Saturday, in hard-hit Jilin City and in the Jiutai district of the city of Changchun.
Nearly half of the cases across China that were announced on Sunday involved people who did not initially show symptoms. China has a very high rate of vaccination, except among the elderly. China has attributed the high number of asymptomatic cases to the prevalence of the highly contagious Omicron variant. A few cases of the Delta variant have also been detected near China’s borders in recent weeks.
Claire Fu contributed research.