Hepatitis B vaccination does not cause hepatitis B infection because the hepatitis B vaccine is purified hepatitis B surface antigen, which is the outer shell protein of the hepatitis B virus and is itself only antigenic and not infectious, and is an inactivated vaccine, a special drug used to prevent hepatitis B. After vaccination, it stimulates the immune system to produce protective antibodies, which exist in the human body. Once the hepatitis B virus appears, the antibodies will immediately act to remove it and stop the infection, and will not harm the liver, thus giving the human body immunity against hepatitis B and achieving the purpose of preventing hepatitis B. At the time of the first vaccination, only 30% of people can produce surface antibodies to hepatitis B, and the effect of antibodies is very unstable. After the second vaccination, 90% of people can produce hepatitis B surface antibodies. After the third vaccination, the antibody rate can reach more than 96%, and the antibody effect can be maintained at a high level.