Hepatitis B is a serious disease caused by a virus that attacks the liver. The virus, which is called hepatitis B virus (HBV), can cause lifelong infection, cirrhosis (scarring) of the liver, liver cancer, liver failure, and death
Some people should not get hepatitis B vaccine or should wait.
People should not get hepatitis B vaccine if they have ever had a life-threatening allergic reaction to baker’s yeast (the kind used for making bread) or to a previous dose of hepatitis B vaccine.
People who are moderately or severely ill at the time the shot is scheduled should wait until they recover before getting the hepatitis B vaccine.