Zhong Nanshan Photo: VCG

A new COVID-19 infection wave in 2023 will likely peak in late June at about 65 million cases per week, China's top respiratory disease expert Zhong Nanshan said Monday.

Zhong made the remarks at the 2023 Greater Bay Area Science Forum on Monday in Guangzhou, South China's Guangdong Province, when he also revealed that two new vaccines to counter the XBB variant will soon be released to the market.

A small wave of COVID-19 infections at the end of April and early May was "anticipated." Projections showed that a small peak of infections is likely at the end of May, with the number of infections peaking at about 40 million per week. By the end of June, the epidemic is expected to peak at about 65 million infections a week.

The second peak won't be as bad as the first, nor will hospitals be overloaded as reinfection usually comes with milder symptoms, Wang Guangfa, a respiratory expert at Peking University First Hospital, told the Global Times on Monday.

But Wang reminded vulnerable groups such as people with underlying diseases to take measures to prevent infection. 

At the forum, Zhong highlighted developing effective vaccines to counter the XBB variant as being critical, since the XBB mutant has become a mainstream strain of COVID-19 in China.

China has approved two COVID-19 vaccines to counter the country's current dominant XBB variant and the new vaccines will soon be released to the market, Zhong revealed at the forum.

He said that three or four more will likely be approved soon. "On developing more effective vaccines, we are running ahead of other countries." 

According to the China Center for Disease Control and Prevention (China CDC), the infection rate of the 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, the China CDC said.

The currently circulating XBB strain variant is a recombinant of Omicron. The data show that its transmissibility and immune escape ability are stronger than those of the early circulating Omicron variant, but there is no significant change in its pathogenicity, according to the National Health Commission.

Data published by China CDC Weekly show that among 368 COVID-19 infections, 104 were infected for the second time, with a larger proportion having received booster shots.  

"The vaccines based on original variants are not designed to prevent infection by 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.