BEIJING — Over 3.1 billion COVID-19 vaccine doses had been administered on the Chinese mainland as of Feb 23, data from the National Health Commission showed on Feb 24.

The number increased by almost 6 million from Feb 22, according to the commission.

On Feb 19, Wu Liangyou, an official with the commission, announced that China's health authorities were rolling out sequential COVID-19 booster vaccinations following the approval of the State Council inter-agency task force for COVID-19 response.

The Chinese mainland reported 85 locally transmitted COVID-19 cases on Feb 23, including 40 in Inner Mongolia, according to the commission.