If no antibodies are produced after the hepatitis B vaccination, you will need to get the hepatitis B vaccination again, with 3 doses. The second dose is required 1 month after the first dose, and the third dose is required 6 months later, when the 3 doses are completed, and then the test is repeated to see if antibodies have been produced. Children should receive the first dose of hepatitis B vaccine at birth, the second dose after the first month, and the third dose after the sixth month. Antibodies to the vaccine last for 2-3 years, and will be tested again when the child is 3 years old and needs to start kindergarten. If antibodies are present, there is no need for the hepatitis B vaccine for the time being, and if they disappear, the child will be re-vaccinated, as will the adult.