Up to 70% of residents in Shanghai may have been infected with Covid, a top Chinese doctor has said.
The steep rise in infections came after China dropped its zero-Covid policy last month, sparking reports of overwhelmed hospitals and crematoriums.
Chen Erzhen, vice president at Ruijin Hospital and a member of Shanghai's Covid expert advisory panel, estimated that the majority of the city's 25 million people may have been infected.
“Now the spread of the epidemic in Shanghai is very wide, and it may have reached 70 percent of the population, which is 20 to 30 times more than (in April and May)," he told Dajiangdong Studio, owned by the Communist Party mouthpiece People's Daily.
Shanghai suffered a gruelling two-month lockdown from April, during which over 600,000 residents were infected and many were hauled to mass quarantine centres.
It comes as China condemned nations requiring Covid tests for passengers travelling from the country and threatened its own “countermeasures”.
The UK is among the nations that will require those coming from China to have a negative test before arrival. The measure will come into force on January 5.
In a briefing on Tuesday, Foreign Ministry spokesperson Mao Ning slammed the measure as lacking scientific basis.
“We believe that the entry restrictions adopted by some countries targeting China lack scientific basis, and some excessive practices are even more unacceptable,” she said.
“We are firmly opposed to attempts to manipulate the Covid measures for political purposes and will take countermeasures based on the principle of reciprocity.”
Alongside the UK, the US, France, and others will require Covid tests on travellers from China, while Belgium said it would test wastewater from planes for new variants.
The government will also carry out surveillance testing of a sample of passengers to try to spot new variants of the virus which could pose a threat.
However, UK ministers confirmed Tuesday that arrivals will not need to quarantine.
Transport Secretary Mark Harper said the move to test those coming into the country on flights from China is about “collecting information" due to the Beijing government refusing to share its own coronavirus data.
Mr Harper, asked if those who test positive after arriving in the UK will be required to quarantine, told LBC: “No, because what we are doing is we are collecting that information for surveillance purposes."
There are no direct flights from China to Scotland, Wales or Northern Ireland but ministers said they are working with the devolved administrations to implement the measures UK-wide.