Inclusion Criteria:  The actual age at the time of admission was higher than 20 years old and birth year after 1987 Born in Taiwan and had received a full course of hepatitis B vaccines at least three doses at infant period. Those who have tested negative for hepatitis B surface antibody and surface antigen at baseline Have never been vaccinated against hepatitis B in childhood and adolescence by questionnaire Consent to administer 1-2 doses of hepatitis B vaccine according to the assigned group after sharing decision making process In good health  Exclusion Criteria:  Those who were previously allergic to hepatitis B vaccine or its components (such as yeast) Those who have been vaccinated against hepatitis B during childhood and adolescence Those who have a positive test for hepatitis B surface antibody or a positive test for hepatitis B surface antigen