In China, it is indeed difficult for adults to be infected with the hepatitis B virus and cause hepatitis B. There are several reasons for this: 1. The immune system of human beings has been well developed in adulthood, and the immune system will produce effective immune defense against the hepatitis B virus after infection with the hepatitis B virus, enabling 95% of adults to clear the hepatitis B virus naturally. 2. Immunization, free planned immunization for newborns has been implemented since 2002. Therefore, the number of people with hepatitis B surface antibodies has increased greatly among those born after 1992. The hepatitis B surface antibody is a neutralizing antibody that neutralizes the hepatitis B virus that enters the body.3. People’s awareness of hepatitis B prevention has greatly increased, and the number of adults receiving hepatitis B vaccination has also greatly increased.4. The number of hepatitis B vaccinations has increased.