What is the smallpox vaccine and how does it work?
The smallpox vaccine was used until the early 1970s to wipe out smallpox worldwide. Much like other vaccines, the smallpox vaccine protects against infection by helping your body develop immunity to the smallpox virus. The smallpox vaccine is made from a live virus that’s very similar to the smallpox virus. The vaccine doesn’t cause smallpox, but it can cause life-threatening problems in some people (especially in people who have a weakened immune system).
