What is mother-to-child transmission of hepatitis B? Mother-to-child vertical transmission of hepatitis B refers to hepatitis B or asymptomatic pregnant women carrying hepatitis B surface antigen (HBsAg) (commonly known as “AoA-positive”), who transmit the hepatitis B virus HBV to their babies during pregnancy or perinatal period through the placenta and birth canal. The baby is born HBsAg positive or turns positive within 6 months or develops hepatitis B. Although the hepatitis B virus is mainly transmitted vertically from mother to child, it is possible for a mother with hepatitis B virus to give birth to a healthy baby if timely and effective interventions are made, a process known as hepatitis B mother-to-child transmission interruption. Because of the high rate of HBsAg carriers in our population (about 12%), about 40% of mothers carry the hepatitis B virus, and about 38%-58% of their children also become HBsAg-positive. Research data show that 90% of them will become chronic HBsAg carriers, which will not only infect healthy people, but may also develop cirrhosis and liver cancer themselves. Therefore, taking countermeasures to control the vertical transmission of hepatitis B virus from mother to child is the main measure to prevent hepatitis B. Interruption. The success rate of mother-to-child transmission of hepatitis B. In order to interrupt mother-to-child transmission, we must first know the route of mother-to-child transmission, which is currently considered to be the infection during delivery, in utero and through the egg. It is a misconception that “injection within 24 hours is sufficient” to stop transmission during delivery, and that “immunoglobulin” should be administered at one’s own expense, as infection during delivery is the most important route of transmission. The strong contractions of the uterus during delivery may squeeze the mother’s blood into the blood of the newborn. Since the virus has just entered the newborn’s blood, if the hepatitis B immunoglobulin can be injected immediately, the hepatitis B virus in the newborn’s blood can be neutralized immediately, and the newborn will not be infected. However, if the injection is given too late (e.g. several hours or even 20 hours later), the virus in the newborn’s blood will have already entered the liver cells and it will be useless to inject hepatitis B immunoglobulin again. Therefore, the earlier the newborn is injected with hepatitis B immunoglobulin, the better. It is completely wrong to suggest that injection within 24 hours is sufficient. The main prevention of infection during childbirth is the administration of hepatitis B immunoglobulin and hepatitis B vaccine to newborns. According to current regulations, hepatitis B vaccine is free of charge, while hepatitis B immune globulin is self-financed. My personal opinion is to mobilize the family to give the newborn hepatitis B immune globulin (HBIG) as much as possible, because the protection effect of hepatitis B vaccine alone is at least half a month later, and it is very difficult to rely on hepatitis B vaccine alone to prevent infection during delivery. Unless the mother’s HBVDNA remains negative during the pregnancy. In this case, it is possible not to give HBIG. This is because the level of infectivity of the mother is closely related to the amount of HBVDNA in her blood. As long as the HBVDNA is positive, it is possible to infect the fetus, and the higher the titer, the more infectious it is. In the second trimester of pregnancy, i.e. July, August and September, pregnant women with hepatitis B should receive one injection of high-efficiency immunoglobulin each, and the baby should be given a combination of hepatitis B immunoglobulin and hepatitis B vaccine as soon as possible within 12 hours on the day of birth, and later the hepatitis B vaccine can be given according to the normal 0, 1 and 6 protocols. What if mother-to-child transmission of hepatitis B fails? During delivery, viral particles can contaminate the baby’s body due to uterine contractions, contamination of maternal blood and vaginal secretions during labor. These contaminated virus particles can be detected in the baby’s blood as the first (surface antigen) and third positive (e antigen) of the five hepatitis B tests. Viral antibodies in the mother’s blood can also enter the baby through the placenta or as a result of contamination during delivery, as evidenced by a positive fourth (e antibody) and fifth (core antibody) of the five hepatitis B tests. However, the positivity of these indicators does not mean that the child has been infected by the mother. By injecting hepatitis B immunoglobulin immediately after birth and receiving the hepatitis B vaccine, most of these viruses contaminated into the baby’s body can be cleared within six months before they infect the liver cells, and very rarely even by 1.5 years of age. However, there are a few children who are born with intrauterine infection, or who are infected because the virus has failed to be cleared by immunization. Therefore, it is not surprising that the virus is detected in the child’s blood shortly after birth. It is generally determined whether the child is infected by the mother only after the child is examined after the third dose of hepatitis B vaccine (7 to 12 months of age). If the child is still positive for the first (surface antigen) and/or the third (e antigen) of the hepatitis B virus in the blood when examined 7 to 12 months after birth, or if the blood is tested positive for HBVDNA, only then can it be basically determined that mother-to-child blockade has failed. Blind treatment is generally not recommended for children too young to be affected. Measures to keep babies away from hepatitis B Three measures to keep babies away from hepatitis B Passive immunization: for children born to pregnant mothers with hepatitis B (acute or recovering), inject hepatitis B human immune serum globulin (HBIG) once within 24 hours after birth, once in March and once in June at a dose of 0.5 to 1 ml, 70% to 80% can be protected. Active immunization: For infants born to mothers with positive surface antigen or/and e antigen, hepatitis B vaccine is given once within 24 hours (or within 7 days) after birth, once in January and once in June, 20-30 μg of plasma vaccine and 5 μg of genetic vaccine each time. Combination injection: The automatic immune response to HBIG-interfering vaccine is not obvious, and its protection rate is 80%-95% when vaccine is given only, but some infants In particular, at least 30% of infants born to e antigen positive mothers will become surface antigen carriers. Therefore, the current trend is to use a combination of hepatitis B vaccine and HBIG to improve the protection rate of infants (up to 85%-95%). The following methods are used: ① HBIG 0.5ml, intramuscularly within 24 hours after birth; ② hepatitis B vaccine 0.5ml (gene vaccine 5μg) and HBIG at the same time, or intramuscularly within 7 days after birth on the other side, and again at 1 and 6 months thereafter; a booster dose of vaccine (gene vaccine 5μg) is administered in 3-5 years. Newborns born to mothers with major and minor triplets should be vaccinated by combined injection as much as possible to minimize hepatitis B infection.