Fever appeared on the 3rd day after vaccination, consider the relationship with the vaccination is not big, because the general vaccination-induced fever is within 24 hours after vaccination, and the duration of the vaccination is also generally 1-2 days. Then 3 days after vaccination, the fever may be caused by respiratory viral infection, at this time, if the child has no other symptoms, you can first carry out fever reduction treatment. If the temperature exceeds 38.5 ℃, the mental state is not good, you can give him some antipyretic drugs, Merrill or ibuprofen, you can also use pediatric antipyretic suppositories anal treatment. If the temperature is below 38.5 ℃, the child’s state of mind is also relatively good, then you can not eat antipyretics, with warm water, wipe, paste a fever patch, and let the child drink more water, the temperature may come down. If the fever is repeated for more than 3 days, and still does not go down, then it is best to go to the hospital to check the blood routine and C-reactive protein.