BEIJING - Nearly 3.44 million over-60s in Beijing, or 80 percent of the city's elderly population, have been vaccinated against COVID-19 as of 4 pm Wednesday, local authorities said.

Over 2.46 million elderly have received booster shots, said the Beijing Center for Disease Prevention and Control.

Over 60.76 million coronavirus vaccine doses have been administered in the city, with over 23 million people now vaccinated. Of all, over 15.4 million have received booster shots, the center said.

A booster shot can significantly increase antibody levels and help prevent infection, particularly reducing the risk of severe illness and death, said the center.

The elderly are particularly vulnerable, with many suffering from chronic, underlying diseases, said Wang Huaqing, an expert with the Chinese Center for Disease Control and Prevention.