Babies with hepatitis B protective antibodies may still be infected. Generally speaking, the presence of hepatitis B protective antibodies in a baby’s body will produce a certain degree of immunity against the hepatitis B virus, which will reduce the probability of being infected by the hepatitis B virus, but it is not absolutely impossible to be infected. If the baby’s resistance is weak or has frequent contact with the hepatitis B virus, there is still a possibility of infection. In addition, if the baby’s hepatitis B surface antibody positive value is less than ten, its probability of being infected will also be relatively high. Therefore, a relatively effective way to prevent hepatitis B virus is to ensure the existence of hepatitis B surface antibody, and if the surface antibody disappears, it is necessary to receive booster shots to enhance immunity. To summarize, even if the baby has hepatitis B protective antibody in his body, there is still the possibility of being infected, therefore, he should pay attention to strengthen the protection in his daily life.