SCMP Explains: What’s in a Covid-19 vaccine?

Countries around the world are ramping up efforts to vaccinate their populations in a race to achieve herd immunity against the SARS-CoV-2 virus. As of March 2021, there are about nine leading vaccines used across various countries and regions, each relying on different forms of technology to trigger an immune response in the body to fight the coronavirus. But what exactly goes into each vial? How different are the components? Here’s what you need to know about the ingredients that make up the vaccines against Covid-19.