Many children will cry at night after vaccination, which may be due to the following reasons: 1. fear of vaccine needles, many children will have fear when they see doctors and nurses in the hospital and see the thick needles for vaccination, thus leaving a shadow will cry at night, parents can hug their children more and stay with them to make them feel safe enough, after 1-2 days the child will forget; 2. Inflammation of the wound will cause pain, and the child will also cry at night; 3. If a mild allergic reaction occurs in the child’s body after vaccination, the body will be uncomfortable and will also cry at night while sleeping; 4. Be alert to the presence of infection, the vaccine itself is a virus that is inactivated, in addition to certain side effects after vaccination, if it is when the child’s immunity is low, such as having fever, cough, jaundice, diarrhea and other If the child has a low immune system, such as fever, cough, jaundice, diarrhea, etc., the child should not be vaccinated, but because of the low immune system, the vaccination will induce infection, and the infection will have different systemic inflammatory reactions, and the child will be uncomfortable at night when sleeping and will naturally cry.