Covid-19: China considers plan for vaccine booster shots

China is considering plans to give vulnerable people a booster shot of Covid-19 vaccine as the Delta variant causes a surge of cases around the world.Shao Yiming, an infectious diseases researcher with the Chinese Centre for Disease Control (CDC), said that so far it seems that the immunity generated by all vaccine types decreases as time goes on, but the body’s immune system does still retain the memory of how to fight the disease.“From initial observations, there is no need for a booster shot…