Hepatitis B immunoglobulin 74642 is like a warrior, specializing in killing the hepatitis B virus, which is not present in the body when the child is first born, and is injected into it intramuscularly as soon as the child is born, so that the child immediately has the ability to kill the hepatitis B virus, making it immune from being infected by the hepatitis B virus, which is passive immunity. The hepatitis B vaccine can stimulate the body to continuously produce protective antibodies by itself, usually in about 1 month, but the amount is relatively small. Over time, the concentration of protective antibodies becomes higher and higher, eventually reaching more than 10-100mIU/ml, forming immunity against the hepatitis B virus, and once this protective power is formed, it can last at least 10-15 years, or even a lifetime, which is called active immunity. Co-immunization of newborns born to mothers with hepatitis B can block more than 95% of vertical transmission from mother to child. Since the popularization of this method in the past 30 years, the incidence of hepatitis B in China has dropped dramatically. As long as the mother is positive for any of HBVDNA, HBsAg, or HBeAg, after the child is born and after flushing of the amniotic fluid, mother’s blood, and vaginal secretions, venous blood is drawn and checked for HBsAg and HBVDNA to determine whether to give another 200 U of hepatitis B immunoglobulin 2 weeks later (rather than checking for HBsAg and HBVDNA in the cord blood, which needs to be specifically noted). Immediate injection of 200 IU of hepatitis B immune globulin in one triceps muscle and 1 dose of hepatitis B vaccine in the other triceps muscle. Because the child has no resistance to the hepatitis B virus at birth, the longer the administration of exogenous protective antibodies is delayed, the greater the chance that the child will be exposed to hepatitis B virus invasion of the liver, so the guidelines call for the injection to be given within 12 hours of birth. If the HBsAb is greater than 100mIU/ml at 7 months of age, the body has developed sufficient immunity and active immunity is successful; if it is less than 10mIU/ml, the body is not sufficiently immune to the hepatitis B virus and needs another booster shot of hepatitis B vaccine, usually according to the 0,1,6 protocol, and follow up accordingly; if the HBsAb concentration is between If the HBsAb concentration is between 10-100mIU/ml, a booster dose of hepatitis B vaccine is recommended for safety reasons. Because the half-life of hepatitis B immunoglobulin is 25 days, if the newborn is positive for either HBsAg or HBVDNA in venous blood, the child should be given a booster injection of 200 IU of hepatitis B immunoglobulin 2 weeks after birth, and if the HBsAg is still positive and the HBVDNA has decreased significantly, the child should be given another injection of 200 IU of hepatitis B immunoglobulin 2 weeks later to If the HBVDNA and HBsAg are negative, the mother-to-child interruption is successful. If the HBVDNA and cord blood concentration do not decrease significantly or continue to rise, it indicates that the child is likely to be infected, and it is not very meaningful to inject hepatitis B immunoglobulin again, and the possibility of successful mother-to-child interruption is very small. If the HBcAb drops significantly, the HBsAb rises significantly (preferably above 100mIU/ml) and the HBVDNA turns negative, the mother-to-child blockade is successful. If the HBVDNA is above the 4th power of 10 at this time, basically mother-to-child interruption can be declared a failure. If the HBVDNA is less than the 3rd power of 10 at this time, you can wait until 18 months of life to review, a small number of children will also turn negative, if the HBsAg also turns negative, then the mother-infant interruption is determined to be successful; otherwise, the mother-infant interruption is clearly declared to have failed.