Is Smallpox Vaccine Really Dangerous?

Vaccines were invented when there was a very clear risk benefit analysis. There are lots of foreign things that the body doesn't create antibodies against because it doesn't register to the immune system as being a threat. You can stell, you'll still produce antibodies against certain things. But if they don't register as a threat, there's a different type of response. It seems to me a similar incident, where, in the early days of poleo vaxine, we used to use a live virus, and that children, in fact, got sick from the poleo Vaxine. They actually contracted poleo from the vexine, rarely, but yes.