Immunization focuses on prevention. Immunization is a way to prevent and control some susceptible diseases through vaccination, a biological agent that has a preventive effect on diseases, while booster immunization is a strengthening of routine immunization. Generally speaking, the immunity (i.e., the ability to resist diseases) passed from the mother to the child’s body gradually weakens or disappears after birth. It is then necessary to administer vaccinations (i.e., scheduled immunizations) at the right time. This is crucial for the health of the child throughout his or her life. For example, in the case of hepatitis B, newborns have a great chance of infection due to their poor resistance. The younger the child is, the higher the chance of becoming a persistent carrier of hepatitis B surface antigen after infection with the virus. For example, children infected with hepatitis B virus within 1 year of age will become chronic carriers of hepatitis B virus in more than 90% of cases, while only 10% of people over 7 years of age become chronic carriers of hepatitis B disease. Therefore, for the health of the child, it is important to receive the hepatitis B vaccine and other vaccines included in the immunization program at the hospital as soon as he is born. Many people believe that only children need to be vaccinated and not adults, which is a misconception. This is a misconception because after vaccination, the corresponding antibodies produced in the child’s body will be targeted to prevent certain diseases, but not once and for all. After a certain period of time, some antibodies will gradually weaken or disappear, thus reducing the preventive effect against the corresponding disease, and then need to be strengthened. For example, after the routine vaccination against hepatitis B, the body will produce surface antibodies to hepatitis B. When the titer of hepatitis B surface antibody is above 10 international units (IU/L), it means that the body is immune to hepatitis B virus and most of them can play a protective role for more than 10 years, on the contrary, if the titer of hepatitis B surface antibody is below this value, the immunization should be strengthened. Nowadays, there is a standardized procedure for routine and booster immunization against hepatitis B: newborns should be vaccinated within 24 hours after birth, with a protection rate of 87.8% for mother-to-child transmission interruption by the vaccine alone and 95%-97% for combined hepatitis B immune globulin (HBIG); newborns of hepatitis B surface antigen (HBsAg)-positive mothers should be injected with HBIG within 24 hours after birth (preferably within 12 hours after birth). The dose of HBIG should be ≥ 100 international units (IU) and 10 micrograms (μg) of recombinant yeast hepatitis B vaccine at different sites, and the second and third doses of hepatitis B vaccine should be given at 1 and 6 months of age, respectively; children who have not received hepatitis B vaccine during the neonatal period should be given a catch-up dose of 10 μg of recombinant yeast hepatitis B vaccine; for immunocompromised or non-responders, the vaccine dose should be increased. For those who are immunocompromised or non-responders, the vaccination dose (e.g. 60 μg) and number of doses should be increased; for those who do not respond to the 3-dose immunization program, they can receive 1 dose of 60 μg or 3 doses of 20 μg recombinant yeast hepatitis B vaccine and have their serum tested for hepatitis B surface antibodies (anti-HBs) 1-2 months after the second dose of hepatitis B vaccine, and if they still do not respond, they can receive another dose of 60 μg recombinant yeast hepatitis B vaccine. China is a big hepatitis B country, with about 130 million people infected with hepatitis B virus, which seriously affects national health and economic development. The combination of planned immunization and booster immunization is the most effective measure to prevent hepatitis B and must be paid attention to.