However, hepatitis B vaccine is not lifelong immunity. With the increase of age, antibodies may gradually weaken or disappear. At this time, it is necessary to strengthen the hepatitis B vaccine, which belongs to the second-class vaccine and is used at its own expense. For adults, if there is no antibody or the antibody is weak, hepatitis B vaccine is also needed. At this time, the hepatitis B vaccine is also self-funded and cannot be used through medical insurance. After hepatitis B vaccination, effective protective antibodies are produced in the body, which can effectively prevent the infection of hepatitis B virus.