China finds first case of more infectious Omicron BA.2.12.1 subvariant

Josephine Ma, South China Morning Post

Posted at May 18 2022 08:02 AM

People under quarantine gather outside their residential compound, amid the ongoing COVID-19 lockdown as China continues to enforce its zero-COVID policy, in Shanghai, China, May 14, 2022. Alex Plavevski, EPA-EFE
People under quarantine gather outside their residential compound, amid the ongoing COVID-19 lockdown as China continues to enforce its zero-COVID policy, in Shanghai, China, May 14, 2022. Alex Plavevski, EPA-EFE
  • Passenger who flew into Guangzhou from Nairobi tested positive while in hotel quarantine on April 27
  • The Chinese man was confirmed to have the subvariant on April 30, according to health authorities

China's first case of the new Omicron subvariant has been found after a passenger who arrived in the country on April 23 tested positive for BA.2.12.1, health authorities said.

They made the disclosure on Monday in China CDC Weekly, the Chinese Centre for Disease Control and Prevention's English-language publication.

The 27-year-old Chinese man had flown into Guangzhou Baiyun International Airport from Nairobi, Kenya and tested positive on April 27 while in hotel quarantine, the report said. He was confirmed to have the BA.2.12.1 subvariant on April 30.

The latest subvariant has been found to be 30 per cent more transmissible than the original Omicron strain, and it has a higher chance of evading immunity from vaccines.

"Several studies have shown that the transmissibility of BA.2.12.1 is about 23 per cent to 27 per cent faster than that of (earlier subvariant) BA.2," the China CDC said in the report.

"(The) Omicron BA.2.12.1 subvariant spreads very fast, which led to the resurgence of the epidemic in many parts of the United States, and cases have been reported in at least 17 countries," it noted.

In the United States, BA.2.12.1 accounted for 36 per cent of samples sequenced during the week ending on April 30, according to the US Centres for Disease Control and Prevention. Average daily cases have roughly doubled since April, and BA.2.12.1 is expected to become dominant in the US, according to CDC data.

BA.2.12.1 was found to evade antibodies from previous infection with the earlier BA1 subvariant of Omicron in a study by Peking University scientists that has not been peer-reviewed. They also found that vaccines offered less protection against the new subvariant in the study, released on the bioRxiv preprint server on May 2.

China's zero-Covid policy has come under huge pressure in the past two months as it struggles to contain local transmission of the highly infectious Omicron strain in major cities including Shanghai and Beijing. The strategy to eliminate cases - which has seen repeated lockdowns of millions of people, mass testing, transport and other restrictions - has taken a heavy toll, and criticism is mounting.

New subvariants like BA.2.12.1 are likely to add to the pressure. Yet the Chinese government says it will stick with the policy, with plans for regular mass testing in all big cities and permanent quarantine facilities to keep the virus at bay.

Ma Xiaowei, head of the National Health Commission, wrote in Communist Party publication Qiushi on Monday that testing booths would be built so that residents could reach them within a 15-minute walk in all provincial capitals and cities with more than 10 million people.

Teams will also be set up to carry out testing so that healthcare workers are not diverted from the hospital system when outbreaks occur. Ma said permanent "cabin hospitals" and quarantine facilities for people who test positive and their close contacts would also be built.

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