Adults also need to check the surface antibody of hepatitis B regularly. Some adults who have been injected with hepatitis B vaccine produce surface antibody, but the antibody does not exist for a lifetime, and when the titer of the antibody is weak, it may become negative, and the chance of hepatitis B infection in adults is relatively higher than that in children. For example, if one of the husband and wife is a hepatitis B virus carrier, he or she may be infected through their conjugal life. In addition, adults may also be infected with Hepatitis B virus through eating and drinking if they often attend parties and do not use disposable chopsticks and spoons, and if they have ulcers in their mouths or ulcers and mucous membrane erosion in their digestive tracts. Adults sometimes go for eyebrow tattooing, tattooing, ear piercing and so on, and when they do not use disposable medical equipment, they may also be infected with hepatitis B virus. Therefore, when there are the above behaviors, it is possible to consume their own antibodies, and after the disappearance of antibodies, the protection against hepatitis B will be gone. Adults should check the hepatitis B two-to-half regularly, and when the titer of surface antibody is less than 10, they should inject hepatitis B vaccine again.