China will start mass COVID-19 vaccinations for people over age 60 after it receives sufficient data from clinical trials on the effectiveness and safety of the vaccines, a senior health official said on Sunday.

Research and development of vaccines for older adults is speeding up, and some regions have started vaccinating people over 60 who are in good health, He Qinghua, an official at the National Health Commission, said at a news conference.

A total of 74.96 million doses of COVID-19 vaccines had been administered by midnight Saturday. The country will gradually increase the scale of its mass COVID-19 vaccinations in a safe, orderly manner, he said.

The free vaccination will be carried out based on the risks of infection of different groups, and participation will be voluntary, He said.

Some people might think it is not urgent for them to get vaccinated as China has successfully controlled the virus, but it is still raging globally and no one can stay detached from the world, he said.

"Vaccination is the most effective way to control the epidemic. I hope the public can get vaccinated quickly," he said.

Mao Junfeng, an official at the Ministry of Industry and Information Technology, said China has steadily increased its COVID-19 vaccine production capacity and can meet the vaccination demands of all people in the country this year.

Manufacturers must make the effectiveness and safety of vaccines the top priority while increasing their production capacity, he added.

Feng Zijian, deputy director of the Chinese Center for Disease Control and Prevention, said China will continue to strictly implement centralized isolation and conduct nucleic acid tests on people entering the country, including those who have been vaccinated, to prevent imported COVID-19 cases.

Different policies will be taken on visa issuance and the number of flights and arrivals based on the levels of vaccination and epidemic control situations in different countries, he said.

China will also keep an eye on the progress of "vaccine passports" and adjust preventive measures once the domestic population has reached a high level of immunity, he said.

The pandemic is still spreading globally, and the vaccination rates in China are still not high enough to achieve herd immunity, so the entry of people or goods from overseas can increase the risks of domestic transmission, Feng said.

In addition, just because a person has already been infected or vaccinated does not mean there is zero possibility of reinfection, he added.

Feng said that all types of current vaccines have proved to be very effective in treating severe cases but not as effective in preventing people from getting infected or treating mild cases, especially considering that the emergence of several mutated variants outside the country might influence the effectiveness of the vaccines.

"Taking these factors into account, the country will continue to adhere to strict epidemic prevention and control measures to prevent imported cases and domestic resurgences of infection," he said. "We will adjust some of the measures in an orderly manner based on the pandemic and vaccination situation."