Vaccine

A vaccine contains a component, such as mRNA or inactivated virus, that can activate the immune system to recognise a specific target (such as a virus-infected cell or cancer cell). It also helps the immune system remember the target in order to prevent future disease. They can be preventative – administered before the onset of the disease, to prevent it in the future, or therapeutic – administered once a disease has already developed to clear the current disease, and reduce the chances of it coming back.