BEIJING--Half of China’s 1.4 billion people will be infected by the novel coronavirus in the coming months, analysts said, based on trends seen after the government eased its “zero COVID-19” policy earlier this month.

The Chinese government stopped releasing data on new cases involving asymptomatic patients on Dec. 14, citing difficulties in determining the number because many of them shun PCR tests.

As a result, figures released by health authorities are significantly lower than the actual number of new cases.

However, an internal document believed to be about a government meeting was leaked on the internet. It showed new infections from Dec. 1 to Dec. 20 totaled an estimated 248 million, or 18 percent of the Chinese population.

If the pace of infections has remained the same, the number of new cases now could exceed 300 million.

Chinese government officials say more than 90 percent of the population have been administered two vaccine doses as protection.

But Tetsuo Nakayama, a specially appointed professor at Kitasato University in Tokyo who specializes in clinical virology, questioned the efficacy of the Chinese-made vaccines.

“The vaccines are made based on a strain originating in Wuhan at an early stage of the pandemic, and they are not effective in fighting the Omicron strain, which is now dominant in China,” Nakayama said.

Some reports have shown the vaccines used in China are not as good as the mRNA vaccines administered in the United States and Europe in terms of protecting patients from serious symptoms and death.

The virus in China is spreading faster than it’s spread ever before anywhere during the pandemic, Ben Cowling, chair professor of epidemiology at Hong Kong University School of Public Health, noted.

He projected that half of the country’s population would be infected before long.

Cowling attributed the recent explosion to the Chinese government’s strict controls under its “zero COVID-19” policy, which he said has left the bulk of the population with little immunity to the virus.

Zhang Wenhong, a leading contagious diseases expert at Fudan University-affiliated Huashan Hospital, has researched the Omicron variant now raging in China.

The basic reproduction number of the strain, or the number of people who could be infected by a single patient, would average 16 to 18 among crowds lacking herd immunity to the virus.

Beijing is reportedly being pummeled by the highly transmissible BF.7 subvariant of Omicron.

But BA.5.2, another Omicron subvariant, is the dominant strain nationwide, according to reports by the Chinese health authorities.

Tetsuya Mizutani, a professor of virology at the Tokyo University of Agriculture and Technology, noted Japan has also been hit by BF.7 and BA.5.2, both of which are derived from BA.5.

“The immunization coverage against the Omicron strain is rising in Japan,” he said. “Even if the subvariants from China find their way into Japan, it should not be particularly concerning to the overall infection situation of the country.”

With little information being released by Beijing on the status of infections, apps that can predict peaks of infections in each region of the country have emerged.

A company collecting data in Shanghai projects the trajectory of infections in each city by comparing the frequency of searches for “fever” on Baidu, the largest search engine in China.

The first peak of infections came on Dec. 17 in Beijing, and 55 percent of the city’s population were infected by Dec. 25, according to the company’s estimate.

Health authorities in Zhejiang province in southeastern China said on Dec. 25 that new daily cases have topped 1 million in the province with a population of 64.57 million. The number is expected to rise to 2 million around Jan. 1, they added.

Chinese leaders are particularly worried about the virus reaching rural areas, where health care systems are typically fragile.

Wu Zunyou, chief expert of epidemiology at the Chinese Center for Disease Control and Prevention, projected his country would experience three waves of infections this winter.

The first wave is expected to hit large urban areas, lasting until the middle of January, while the second wave would strike between late January and the middle of February, when people travel to their ancestral homes in local regions for the Chinese New Year holidays.

The third wave would likely be from late February to the middle of March, when people return to the cities.

(This article was written by Ryo Inoue in Shanghai and Masayuki Takada in Beijing.)