All nine million people in a major Chinese port city will be tested for Covid-19 after authorities reported a tiny cluster of coronavirus infections in Qingdao.
The outbreak snaps a streak of over two months without local transmission and underscores the risk of resurgence in countries that have achieved near-eradication of the pathogen.
The virus has been largely brought under control in China – where it first emerged last year – in stark contrast to many parts of the world still afflicted by rolling lockdowns and high case numbers.
The city in Shandong province said on Sunday that it found three asymptomatic cases linked to a hospital which treats 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 under way and aims to cover the entire city of more than nine million within five days, the local health commission said on Monday.
China has extensive, quick test capabilities and by noon on Monday the health commission said more than 277,000 people had already been tested in Qingdao, with nine positive results.
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.
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 per cent of the level from a year ago, reflecting the country’s confidence that mass travel with few restrictions will not result in uncontrollable new flare-ups.
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.