China has approved two COVID-19 vaccines to counter the country's currently dominant XBB mutated variant and the new vaccines  will soon be released to the market, China's top respiratory disease expert Zhong Nanshan revealed Monday.

Zhong said a small wave of COVID-19 infections at the end of April and early May was "anticipated", and the XBB mutant has become a mainstream strain of COVID-19 in China.

According to the data disclosed by the China Center for Disease Control and Prevention (China CDC), the infection rate of XBB mutant increased from 0.2 percent in mid-February to 74.4 percent in late April and then to 83.6 percent in early May.

The proportion of infections linked to the variant continues to rise, China's CDC said.

Zhong highlighted developing effective vaccines to counter the XBB variant as being critical. He said two vaccines targeting XBB have been initially approved, and that three or four more will likely be approved soon.

"On developing more effective vaccines, we are running ahead of other countries," Zhong said in remarks made at the 2023 Greater Bay Area Science Forum held on Monday in Guangzhou, South China's Guangdong Province.

Data published by China CDC Weekly show that among 368 COVID-19 infections, 104 had infected for the second time, with a larger proportion having received booster shots. It triggered many to speculate whether vaccines still offered efficacy against the virus.  

"The vaccines based on original variants are not designed to prevent infection from new variants. The former cannot induce sufficiently effective neutralizing antibodies against the mutated strain, whereas the new generation of vaccines, which are more targeted, can induce sufficient and effective antibodies," Xie Liangzhi, chairman of Beijing-based SinoCellTech said.

Effective vaccines must be updated just as vaccines against the flu are adjusted to target new variants each year, Xie noted.