It is recommended to take a bath after 2-3 days after your baby has received the hepatitis B vaccine, because after vaccination, there will be a needle mark on the arm, and the injection site should not be exposed to water until the mark has healed, otherwise it may cause infection, so you can’t take a bath immediately after vaccination. Moreover, the body’s immunity is relatively low after vaccination, and bathing is also prone to catching cold and catching a cold. After vaccination, parents should prepare a comfortable environment and let the baby rest more to relieve the discomfort brought by the body after vaccination. Observation should also be strengthened. If there are redness, swelling and hard nodules at the injection site, it is usually not necessary to deal with them and the symptoms will disappear within 2-3 days. If the symptoms of low fever, loss of appetite, nausea, diarrhea, belong to the normal immune response after vaccination, the symptoms will disappear in 1-2 days, if there are symptoms of high fever, it is recommended to seek immediate medical attention.