Random passengers on direct flights from mainland China into the UK are to be tested for COVID-19 in a new UK Health Security Agency (UKHSA) surveillance programme which starts today.
Concern is growing that COVID is overwhelming the health system in China as the virus continues to spread through a large population which possesses little immunity thanks to the government's now scrapped Zero-COVID policy, which relied on isolation rather than inoculation.
There are also fears about how accurate the country's data is over the outbreak.
It is anticipated the currently low numbers of travellers from China will increase from today, as quarantine requirements on return to China are removed, so the new surveillance will begin.
Since 5 January, people travelling from mainland China have been asked to take a pre-departure COVID-19 test.
But the UKHSA said its new programme would also see "a sample of passengers arriving in England from mainland China tested for COVID-19 at the point of their arrival".
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The agency said passengers at Heathrow would be invited to take part in the study and all positive samples sent for sequencing.
"This will further enhance the UK's ability to identify any new variants which may be circulating in China that could evade the immune response of those already vaccinated, or which have the potential to successfully outcompete other variants and spread internationally," an agency statement explained.
Secretary of State for Health and Social Care Steve Barclay said as China reopened its borders, it was "right for us to take a balanced and precautionary approach by announcing these temporary measures while we assess the data".
He added: "This allows our world leading scientists at the UK Health Security Agency to gain rapid insight into potential new variants circulating in China."
The end to Zero-COVID rules at the beginning of December has unleashed the virus on China, which is home to 1.4 billion people.
The population has little immunity after being shielded since the coronavirus emerged in the Chinese city of Wuhan in late 2019.
Many funeral homes and hospitals say they are overwhelmed, while international health experts have warned of at least one million deaths in China this year.