Recently, several hepatitis B mothers who were afraid of failure of mother-to-child blockade after the birth of their children repeatedly had their children’s blood tested for hepatitis B antibodies and wrote to me asking, “The antibodies were over 100 when I was born 1 month ago, but now 2 months later, the antibodies have dropped to over 70, do I need another injection of hepatitis B immunoglobulin?” “How high are antibodies considered immune?” In the “Hepatitis B Vaccine: WHO Position Paper” published by the World Health Organization in 2009, it is stated that if the antibody level is tested 1 to 3 months after receiving 3 doses of basic immunization against hepatitis B vaccine, the body is considered to have the ability to defend itself against hepatitis B virus infection if “the anti-HBs antibody is ≥10 mIU/ml.” Therefore, babies born to hepatitis B mothers are routinely injected with hepatitis B immunoglobulin and vaccinated with hepatitis B vaccine after birth, and generally have sufficient antibodies in their bodies. Therefore, hepatitis B mothers do not need to repeatedly take blood tests for their children. After I replied to the hepatitis B mother, she wrote to me again and asked, “Why do you tell parents that their child’s antibody is not too high and needs a booster shot of hepatitis B vaccine if the antibody is < 100 mIU/ml after 3 shots? My child is now 2 months old and his antibodies have dropped to over 70, so his antibodies are not too high!" Let's look again at the World Health Organization's Hepatitis B Vaccine: a WHO Position Paper. In the paragraph on the duration of antibody protection and the need for booster immunization, the WHO states, "The higher the peak anti-HBs titer after hepatitis B vaccination, the longer it takes for it to fall to ≤10 mIU/ml." Therefore, if the antibodies are < 100 mIU/ml after completing 3 doses, the child is considered to have a "low response" to the hepatitis B vaccine, and although immunity to the hepatitis B virus is present, this immunity may be short-lived and the child is recommended to receive a booster dose of hepatitis B vaccine. However, the child has not received the third dose of hepatitis B vaccine at the age of 2 months. When the 3rd vaccination is given, the antibodies will rise automatically. Therefore, parents should not be too anxious. Newborn babies have poor resistance, and there are more viruses and bacteria in the hospital, so repeated visits to the hospital will instead increase the child's risk of contracting other diseases. Nowadays, mother-to-child blocking technology has been developed more maturely, and most of the hepatitis B mothers will give birth to healthy babies.