Most of the adverse reactions after vaccination of children are as follows: 1. Causing redness, swelling, heat and pain in the local area of vaccination. When children are vaccinated, most of the vaccines are injected into muscular areas, such as the deltoid muscle or gluteus maximus muscle, which can cause redness, swelling, heat and pain in the local area of the vaccination. This is the most common adverse reaction. 2. Non-specific systemic symptoms in children, such as fever, drowsiness, anorexia, poor mental status, etc. 3. Specific vaccination reactions. Rotavirus vaccination in children can cause mild diarrhea. In case of influenza vaccination, it can cause headache and vomiting in children.