The Hepatitis B vaccine given to children at birth lasts for about 5 to 10 years, but the exact duration is not fixed and needs to be determined on a case-by-case basis. Typically, children usually receive their first dose of hepatitis B vaccine at birth, followed by one injection in the first month and one in the sixth month. A total of three injections is called the 0-1-6 injection process. The Hepatitis B vaccine that a child receives at birth is not necessarily a lifetime immunization. Hepatitis B vaccination results in the production of protective antibodies in the body that can fight off the invasion of the hepatitis B virus from the outside. However, with the growth of time, the titer will gradually decline or even disappear. In this case, it is necessary to re-vaccinate with the hepatitis B vaccine to increase the level of antibodies. Therefore, after receiving the hepatitis B vaccine, it is necessary to go to the hospital for regular checkups to clarify the level of antibodies in the body.