Beijing,  Over 3.1 billion Covid-19 vaccine doses had been administered on the Chinese mainland, so far, data from the National Health Commission showed Thursday.

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

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

The Chinese mainland on Wednesday reported 85 locally transmitted Covid cases, including 40 in Inner Mongolia, according to the commission.