Babies may have reactions to the hepatitis B vaccine, but the chances are not high. Hepatitis B vaccine is a relatively safe attenuated vaccine, after vaccination, it can produce effective hepatitis B surface antibodies in the body, which can be used to fight against hepatitis B virus infection, and most babies will not have any adverse reactions after vaccination, so the safety is relatively high. However, due to the different physique of individuals, some babies may have fever, rash, localized redness and swelling and other adverse reactions after vaccination, but most of them can subside by themselves in about 4 days and do not need special treatment. Hepatitis B vaccine needs to be vaccinated in a healthy state, if the baby has sick symptoms or is sick, it is not allowed to vaccinate hepatitis B. After vaccination, you need to maintain a light diet.