Nearly one million people have taken an experimental coronavirus vaccine developed by China National Pharmaceutical Group (Sinopharm) through the country's emergency use programme, the firm said.

"No serious adverse reaction has been reported from those who received the vaccine in emergency use," Sinopharm said in an article on WeChat, citing Chairman Liu Jingzhen from a recent media interview.

Two vaccine candidates developed by Sinopharm's subsidiary China National Biotec Group and third one developed by Sinovac Biotech have been used for the emergency programme, according to Reuters.

It's unclear which vaccine Liu referred to, and Sinopharm was not immediately available to comment.