Staff inspect the sterile needles and syringe bottles for the COVID-19 vaccine. Photo: Li Hao/GT

China is calculating how many people working in high-risk professions, including cold-chain, medical and port workers, will need to receive COVID-19 vaccines, health officials said Monday.

Experts said the mass vaccination of ordinary people is likely to be rolled out in the second quarter of 2021, when vaccines are officially allowed to enter the market.

Previously, the Global Time learned that China is planning to vaccinate 50 million people in high-risk groups before Chinese New Year which falls on February 12. That number was not confirmed by officials at the conference.

Tao Lina, a Shanghai-based expert on vaccines and a former Shanghai disease prevention and control employee, told the Global Times on Monday that vaccination of some 50 million people in high-risk professions before Spring Festival could prevent a potential infection rise caused by the travel rush.

After the first shot, people could produce a low level of antibodies, but after the second shot, the rate of antibodies is likely to reach 95 percent in about a week, Tao said, adding that "the generated antibodies of those 50 million people will return us to a safe Spring Festival."

The Spring Festival travel rush is also known as the world's biggest annual human migration. About 2.97 billion trips were made in 2018 Spring Festival travel rush and about 2.98 billion in 2019. The Spring Festival travel rush will start on January 28, 2021 and end on March 8, authorities said.

But Tao said vaccines against COVID-19 will not be open to the general public until vaccines are officially allowed to enter the market.

Also, after the first 50 million people get vaccinated, the risks of an epidemic will be largely reduced, which reduces the urgency of vaccinating everyone, the expert said.

Only when 70 percent of the population are vaccinated will China reach herd immunity against the novel coronavirus, Chinese officials said, appealing for the public to take the vaccines.

Zheng Zhongwei, director of the Development Center for Medical Science and Technology of the National Health Commission (NHC) dismissed concerns on the safety of Chinese vaccines on Monday. Nearly 1 million people have been vaccinated voluntarily. China has carried out phase I, II and III clinical trials, which have demonstrated that Chinese vaccines are safe. "There are some minor adverse reactions, but no serious ones," Zheng said.

China is ready for mass production of COVID-19 vaccines and will proceed with the official approval process as soon as possible after the release of phase-III interim clinical data, health officials said at the press conference.

In the second stage, the population to be vaccinated will expand to groups including the elderly and people with other diseases. "Our goal is to strive to establish the protection of herd immunity, so that the epidemic can be controlled more effectively," Zeng Yixin, an official from National Health Commission, said on Saturday.

The vaccination of key populations has already begun. In addition, health officials stressed that it is still necessary to take personal precautions, as the protection rate of vaccines is not 100 percent.