Elsewhere, millions of people are being confined to their homes in Xi’an and Yuzhou, two cities that are farther away but have larger outbreaks. Both have been traced to the delta variant. The outbreak in Yuzhou is also affecting Zhengzhou, the Henan provincial capital 40 miles to the north. Zhengzhou has been conducting mass testing and is closing schools starting Monday.
The first two cases confirmed in Tianjin were a 10-year-old girl and a 29-year-old woman working at the after-school center. Both were infected by the omicron variant. In subsequent testing of close contacts, 18 others tested positive and 767 tested negative as of Saturday night.
Those infected include 15 students from 8 to 13 years old, the after-school center staff member and four parents. The citywide testing is to be completed over two days. Tianjin has also closed some subway stations on two lines to try to prevent further spread.
China had reported about a dozen omicron cases previously, most among people who had arrived from abroad and were isolated. In one case in mid-December, the infection was not detected until after the person had completed two weeks of quarantine, and it spread to a few close contacts in the southern city of Guangzhou.