Imported COVID-19 infections, sporadic local outbreaks and constant virus mutations have all threatened to disrupt China's stable epidemic control situation, experts said on Thursday, urging the public to get vaccinated as soon as possible while also abiding by personal hygiene measures.

Preliminary research shows that China's COVID-19 vaccines currently in use can provide protection against new variants first detected in India to a certain extent, said Shao Yiming, a researcher from the Chinese Center for Disease Control and Prevention.

During an earlier interview, he had already confirmed the efficacy of domestic vaccines against variants from South Africa, the United Kingdom and Brazil.

"The inactivated vaccines widely used in China can be conveniently altered to tackle new virus strains. Relevant departments are keeping a close eye on virus mutations and new vaccines will be developed and rolled out if the situation requires it," he said.

The COVID-19 pandemic has largely remained under control in China for more than a year, but the recent outbreak affecting Anhui and Liaoning provinces has sounded the alarm that the fast spread of the virus overseas will continue to pose new risks and stringent virus control measures should not be relaxed for one second, said Wu Liangyou, deputy director of the National Health Commission's disease prevention and control bureau.

The outbreak that surfaced on May 13 had led to 21 confirmed infections as of Wednesday, according to the commission. The most recent case, which was confirmed on Wednesday, is a cold-chain worker in the port city of Yingkou in Liaoning.

Wu Zunyou, a chief expert at the China CDC, said based on mass testing results conducted in the two provinces, the outbreak will not be on a large scale and those new infection clusters are bound to be triggered by imported cases or contaminated goods from overseas.

"As long as the virus' spread overseas is not reined in, any region in China is at risk of seeing new infections," he said."As a result, the public must stick to personal protective measures, such as wearing masks."

Mass vaccination is another crucial way to fend off fresh risks, said Wang Huaqing, a chief expert at the China CDC.

"It is not encouraged to seek inoculation only when a new outbreak arises. The nationwide immunization program is proceeding in an orderly manner, so everyone should go and get vaccinated upon receiving notification," Wang said.

The commission said China had administered nearly 450 million doses as of Wednesday and over 100 million doses were provided in the past eight days.

Zhong Nanshan, a renowned respiratory expert, said it is likely that human beings will coexist with the virus in the future.

He added that if the length of immune response from vaccination is shorter than a year, vaccination should be given annually, "similar to influenza vaccines".