China's reporting of its first imported case of Omicron variant BA 2.12.1, the most transmissible COVID-19 variant identified to date, proves that the global pandemic is still in high gear and China should uphold its dynamic zero-COVID policy, Chinese experts said.

On April 23, a 27-year-old Chinese man flew to Guangzhou, Guangdong province, from Nairobi, Kenya, and tested positive on April 27 during hotel quarantine, according to a report released last week by the Chinese Center for Disease Control and Prevention. He was confirmed to have the BA 2.12.1 subvariant on April 30.

In another report, the China CDC said a Chinese female passenger arriving in Guangzhou from Amsterdam, Netherlands, was found on May 4 to be carrying the Omicron subvariant BA.4, another variant of concern recently identified in South Africa.

The China CDC noted that the transmissibility of BA 2.12.1 was about 23 to 27 percent higher than that of BA.2, the ancestor strain of BA 2.12.1 that has caused multiple outbreaks in China including in the municipalities of Beijing, Shanghai and Tianjin, and in provinces such as Jilin, Shaanxi, Guangdong, Shandong and Zhejiang.

On May 4, the World Health Organization urged countries to closely monitor BA 2.12.1, which has been detected in over 23 countries as of May 11. It is poised to displace BA.2 as the dominant strain in the United States since New York state first identified BA 2.12.1 back in April.

The China CDC report had spurred public discussion on Chinese social media, with some worried that China will be hit by another wave of COVID-19 outbreaks triggered by the new Omicron strain.

An epidemiologist familiar with the China CDC report told China Daily that there is no need to panic as the two imported cases were discovered in quarantine and did not lead to community spread.

On Sunday, the Guangdong local health authority reported zero confirmed cases in the province and one asymptomatic case in the city of Zhaoqing.

"The highly contagious BA 2.12.1 reaching the Chinese mainland for the first time is a serious reminder that the virus is constantly changing, and that fighting the COVID-19 pandemic is still an uphill battle," the expert said.

"This further highlights the importance of preventing the coronavirus from entering the country and causing new outbreaks."

Despite being more transmissible, there is not enough evidence to suggest that BA 2.12.1 can cause more severe illness than BA.2, the expert said.

Moreover, an increase in COVID-19 hospitalizations, as in the US, does not necessarily mean that people are getting sicker due to BA 2.12.1. It might be due to people being hospitalized for other conditions and then testing positive for COVID-19, which is a likely scenario given how prevalent the new strain is in the US after the country recently relaxed many of its epidemic control measures, the expert said.

"There is still much we don't know about the new Omicron subvariant, so we need to be vigilant and prepared," the expert noted.

"Meanwhile, current vaccines and non-medical interventions, such as mask wearing and social distancing, are still effective in protecting the public against BA.2 and BA 2.12.1."

The priorities for China's anti-epidemic effort should still focus on increasing vaccine coverage for the elderly, especially those with underlying health conditions, and upholding the dynamic clearance strategy by enhancing testing and medical capacities, the expert said.

Ma Xiaowei, head of the National Health Commission, said China will need to take faster and more decisive actions to prevent and control new outbreaks caused by the Omicron variant, such as conducting regular nucleic acid tests and bolstering local medical resources.

Local authorities should also prepare sufficient designated hospitals, permanent makeshift hospitals and centralized quarantine facilities, he said in a signed article published last week in Qiushi Journal, the flagship magazine of the Communist Party of China Central Committee.

Most of the makeshift hospitals in China are temporary facilities set up in stadiums, exhibition centers, schools and other buildings to accommodate infected cases with no or mild symptoms.

Testing booths will be built in provincial capitals and cities with more than 10 million people so that residents can access them within a 15-minute walk, thus making weekly mass screening possible, Ma wrote.

"We have to sufficiently recognize that 'lying flat' and 'living with COVID' will result in massive public health and socioeconomic costs," Ma said.

Wu Zunyou, chief epidemiologist at the China CDC, said on social media on Friday that it is necessary to conduct routine mass screening to find and quarantine all Omicron carriers from communities because many infected are asymptomatic and may be silently spreading the virus without their knowledge.