Hepatitis B is caused by hepatitis B virus infection, and hepatitis B virus infection in the neonatal period mainly refers to HBV infection most of which passes chronically and can often persist and become chronic carriers or chronic hepatitis, seriously affecting the health of children. The relationship between this condition and chronic liver failure has been gaining attention. At least 10% of neonatal hepatitis B vaccinations will fail, 100 units of hepatitis B immune globulin only provide effective protection for 3 months, and mother-to-child transmission of hepatitis B virus is not just in utero and during delivery. Hepatitis B in newborns I. Can all newborns produce antibodies with the hepatitis B vaccine? The hepatitis B vaccine is prepared by genetic engineering according to the outer membrane protein of the hepatitis B virus. There are two components in the outer membrane protein of the virus: pre-S1 and surface antigen. Pre-S1 must carry the entire virus into human liver cells for hepatitis B transmission; surface antigen is taken up by human lymphocytes to produce surface antibodies. The lymphocytes produce pre-S1 antibodies that prevent the virus from invading the liver cells; the surface antibodies prevent hepatitis B virus transmission. The current hepatitis B vaccine is made using only surface antigen and not pre-S1. More than 10% of newborns are not sensitive to surface antigen vaccine, and almost all newborns can produce antibodies to outer membrane proteins if the vaccine contains pre-S1 components. Why are vaccines prepared without the pre-S1 component? It is because it is not cost-effective. If 9 children in kindergarten have surface antibodies and 1 child has no antibodies, they are called susceptible children. If a person with “major triplet” is infectious in the kindergarten, one susceptible child is separated by nine immune children around him/her, so he/she can rarely be infected. Individual susceptible children are infected in the community, plus a very small number of children are infected by mother and child, constituting the current prevalence of hepatitis B virus infection in China’s children about 1%. B. What is the difference between the immunization effect of hepatitis B vaccine and immunoglobulin? The hepatitis B vaccine is administered according to the 0-1-6 months program, and the antibody produced by each injection is slightly less than 30%, and the highest level of surface antibody can be produced only when the full program is completed at 6 months. Children produce surface antibodies from their own lymphocytes after vaccination, which is called “active immunity”. In adults, for example, if the spouse of a person with “major triple-positive” infection is a susceptible person without antibodies, healthy adults are rarely infected, and the virus invades (as in the case of hepatitis B vaccination) to produce immunity instead, and most newly susceptible spouses produce surface antibodies (also active immunity) after one year. Once the virus has turned negative in a “major triple-positive” infected person, the spouse will automatically stop producing antibodies without viral stimulation, leaving the surface antibodies gradually decreasing and turning negative after 3 to 4 years. However, the lymphocytes that have produced antibodies already have an immune memory, so if the virus rebounded in a “major triple-positive” infected person, the spouse’s antibodies would spike within a week. Therefore, there is no need for a booster vaccination, and certainly no need for further testing, as long as the active immunization is successful. Back to the pediatric population, if there is someone with a high level of hepatitis B virus in the family, there is a risk of infection before the vaccine program is completed and hepatitis B immune globulin must be administered. Hepatitis B immunoglobulin is prepared by extracting and concentrating blood from blood donors with very high levels of surface antibodies, and is a very pure surface antibody that provides immediate protection for newborns after 100 units (1 injection), and the effective level of protection can be maintained for 3 months. Because antibodies are not produced by our own lymphocytes, those obtained by injecting globulin are called “passive immunity”. C. Transmission from mother to child in daily life? In close contact with the mother and child in daily life, the virus can be transferred directly from the carrier to the susceptible child through broken skin and mucous membranes (including eczema, scabies, oral ulcers or erosions). It may also contaminate some toys or furniture, women’s underwear (especially during menstruation) can contaminate washing machines or basins, and the hepatitis B virus has a strong life force and can survive for up to 1 month outside the body. Young children often bump and bang and suffer minor trauma, and toys are often used as carriers to pass on the virus. Carriers of “major triple-positive” have a high viral content and release large amounts of virus to contaminate environmental surfaces.