Smallpox is prevented by vaccination and controlling its spread by:isolating and vaccinating infected people. The smallpox vaccine helps the body develop immunity to smallpox. The most common side effects from the smallpox vaccine are a sore arm, fever and body aches. Reactions to the vaccine range from mild rashes to rare fatal brain inflammation. Complications and some life-threatening side effects are particularly common in people with immune deficiencies and skin disorders.
Attribution: Straight Talk Foundation