China has administered 164.47 million doses of COVID-19 vaccines as of Saturday, becoming world's second most-vaccinated country after the U.S., said Wu Liangyou, deputy director of the National Health Commission (NHC)'s disease control bureau on Sunday in Beijing, China.

China is undertaking vaccination in an orderly manner, prioritizing key groups, high-risk groups and other groups, thereby steadily improving vaccine coverage, according to Wu. 

The key groups include people at high risk of virus exposure at work, people at risk of infection from abroad, people who work at key positions that maintain the basic operation of the society, individuals aged over 18 who are in border regions or work in services or labor-intensive industries, and elderly who are in good physical condition and need to be vaccinated for special reasons.

Meanwhile, China's National Health Commission also encourages more people to get vaccinated against COVID-19 on a voluntary, informed basis instead of a compulsory one, said Mi Feng, a spokesperson for the commission, at the Sunday press conference.

Furthermore, Wang Huaqing, the chief immunologist at the Chinese Center for Disease Control and Prevention, said that in order to build an immune barrier in China, more than one billion people need to be vaccinated. "The higher the vaccination rate is, the stronger the immune barrier will be. We still have a long way to go," he said.