CHINA reported a new cluster of coronavirus infections in the eastern port city of Qingdao, snapping a streak of over two months without local transmission, underscoring the risk of resurgence in countries that have achieved near-eradication of the pathogen.

The city in Shandong province said on Sunday that it found three asymptomatic cases linked to a hospital which treats coronavirus disease 2019 (COVID-19) patients coming from abroad. Expanded testing of hospital patients and staff then found another nine infections — of the total of 12 in the cluster so far, six are asymptomatic.

More testing is underway and aims to cover the entire city of 9.5 million within five days, the local health commission said on Monday.

The cluster has now become China’s biggest in months, reflecting the difficulty of stamping out the coronavirus in any one country when outbreaks are still spreading rapidly in places like India and the US while rebounding in Europe. Several nations in the Asia-Pacific region like Thailand and New Zealand have also maintained long stretches of virus-free periods, only to see the pathogen rear its head again.

“A single moment of negligence may provide a way in for the virus under the radar, and then it’ll cause several domestic cases,” said Zhang Wenhong, director of infectious diseases at Shanghai Huashan Hospital, who advises the local government on containment strategy. “This is the risk we need to raise our response against.”

Still, the new cluster is unlikely to interrupt China’s progress in moving past COVID-19 as its economy rebounds and life returns to normal for the vast majority of citizens. A national eight-day holiday period that just concluded saw 637 million trips made domestically, 80% of the level from a year ago, reflecting the country’s confidence that mass travel with few restrictions won’t result in uncontrollable new flareups.

The sources of these resurgences remain largely a mystery, as asymptomatic carriers prevent health experts from being able to map a chain of transmission. Last month, Qingdao also found two port workers -— responsible for unloading frozen seafood — who tested positive in routine checks without showing symptoms.

China has suspended frozen food imports from plants in several countries after detecting the virus on the packaging or surface of imported meat and seafood.

Authorities in Qingdao are now sticking to the same playbook China has used in curbing resurgences after it contained the initial deadly outbreak in Wuhan. Amid mass testing and contact-tracing, all who test positive are isolated and quarantined, regardless of symptoms. — Bloomberg

RELATED ARTICLESMORE FROM AUTHOR