Side effects related to the hepatitis B vaccination are mild, including slight soreness where the shot is given or mild fever, according to the Centers for Disease Control and Prevention. As with any vaccination, there is a possibility of an allergic reaction, but the risk is very small.
An allergic reaction that may cause serious medical issues or death is estimated to occur once in every 1.1 million people, notes the CDC. The hepatitis B vaccination is not an infectious agent, meaning recipients cannot contract hepatitis from the vaccination. The risks for a person who does not get the hepatitis B vaccination are much more serious in nature, as people who contract hepatitis often develop liver cancer or cirrhosis of the liver.