Yangquan in North China's Shanxi province recently rolled out a sequential booster immunization system against COVID-19, which consists of booster shots based on technologies different from those used in initial inoculations.

According to experts from the Yangquan Center for Disease Control and Prevention, sequential booster immunization can prevent side effects brought about by a certain type of vaccine. 

Both sequential booster immunization and homologous booster immunization can greatly increase the level of neutralizing antibodies in patients and further strengthen immunity.

People aged above 18 who have received two shots of inactivated vaccines produced by Sinovac, Sinopharm Beijing or Sinopharm Wuhan at least six months ago can receive the sequential booster shots. 

Residents of the city can follow the latest information on the public WeChat account of the Yangquan Center for Disease Control and Prevention and visit a nearby vaccination site for sequential booster immunization.