In Harbin and Suihua in Heilongjiang, 11 Covid-19 cases and three who were yet to show symptoms were reported on Sunday.
All these newly registered infections were detected in the testing of people under quarantine, according to the Harbin municipal government.
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Heilongjiang was on high alert after the first three local cases were reported in Harbin on Tuesday last week. A panel of experts and Ma Xiaowei, director of the National Health Commission, visited the province to offer guidance in managing the outbreak.
Experts said epidemic control was challenging because the outbreaks involved several counties – Mulan, Bayan and Songbei – and the neighbouring city of Suihua, where people travelled frequently.
Several confirmed cases also went to weddings and the Harbin government called on people who had attended those 11 weddings to be isolated.
Bayan county ordered residents not to leave their homes and to have necessities such as food delivered to the door.
Xu Bin, a testing specialist from Jiangsu province who went to Heilongjiang to help, said the key to blocking transmission was rapid testing, contact tracing, quarantine and neighbourhood control.
“Our goal is to gather a wide range of samples, deliver them [for testing] frequently, test rapidly and report results precisely, so that we can find infections in time to block the chain of transmission,” Xu told state broadcaster CCTV.
By Saturday, Harbin had completed two rounds of citywide testing and a township in Bayan county, the centre of the outbreak, had completed four rounds, with a fifth under way.
Zhang Boli, a medical expert and academician of the Chinese Academy of Engineering, said sporadic outbreaks in winter were unavoidable and China needed to be on high alert.
“The Delta virus is the dominant strain and is really contagious – one person can infect several or even dozens and it spreads quickly,” Science and Technology Daily quoted Zhang as saying.
“Although we have taken strict measures to prevent importation, we cannot completely close our doors and more and more people are coming back.
“This autumn and winter, we still need to be vigilant. Local, multipoint outbreaks cannot be completely avoided and require increased vigilance.”
China would need to step up vaccination, he said. Immunisation may not be as effective as before against transmission, but vaccines still could prevent severe cases and death.
Zhang said it was a “beautiful wish” to live with the coronavirus but that could only be achieved when some conditions were met – and now was not that time.
“Our battle with the Covid-19 is now in a stalemate, and we still need to prevent local outbreaks from imported cases and community spread. We need to stick to some proven methods and measures to actively promote vaccination and strive for herd immunity,” he said.
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