A vaccine is a dangerous thing that people take hoping to stave off something worse.

The reason doctors tell us it is safe is because vaccines are quite obviously is dangerous. While the medical machine is trying to weighs known dangers against potential dangers.

BTW, if you want to make a statist angry; you can point out that vaccines are based on the same principle as homeopathic medicine...you expose a kid to a small amount of a problematic substance to build up resistance. I launched a statist on a twenty minute tirade by comparing something he likes (mandatory vaccines) to a thing he hated (natural medicine).