BEIJING -- China has called for joint efforts to further improve the vaccination rate among the elderly and other key groups, a Chinese health official said Friday.

China has seen a generally smooth COVID-19 vaccination drive, and the vaccination rate among the elderly is also gradually increasing, Lei Zhenglong, an official with the National Health Commission, told a press conference.

As of Thursday, more than 3.34 billion COVID-19 vaccine doses had been administered across the Chinese mainland, and around 1.25 billion people had been fully vaccinated, Lei said.

By Thursday, around 227 million people over the age of 60 had received at least one shot, representing 86.01 percent of the elderly population, while over 215 million seniors had been fully vaccinated, Lei added.