After three doses of hepatitis B vaccine, 96% of the population will develop sufficient and stable protective antibodies, which will generally remain in place for 12 years, or an average protection period of 12 years. Although 96% of the population produces protective antibodies, there are 4% of the population that do not. This group has received three doses of the hepatitis B vaccine but has not developed protective antibodies, which means that they are not protected against hepatitis B virus infection. In order to achieve the goal of preventing hepatitis B virus infection, this group of people needs to be immunized with a one-year interval and receive a booster dose of hepatitis B vaccine. Even after the hepatitis B vaccine booster, only 50% of these people will develop protective antibodies. Therefore, the hepatitis B vaccination is not foolproof, and the five tests for hepatitis B should be performed to see if protective antibodies, or hepatitis B surface antibodies, have been produced.