How long it takes for a child to take medication after vaccination cannot be generalized, but needs to be analyzed according to the child’s constitution and specific health condition. For children who are completely healthy and have no discomfort after vaccination, medication can usually be taken 6-12 hours after vaccination. If the child develops fever, rash, dermatitis, localized redness and swelling for a short period of time after vaccination, don’t worry too much, it is a normal phenomenon after vaccination, and it is better to wait for the improvement of the above symptoms before using the medicine. If the child has other symptoms besides those mentioned above, it is recommended to consult a professional pediatrician to identify the specific cause, and select the appropriate medication according to the cause of the illness and use the medication on time. In addition, if a child who has just been vaccinated is not feeling well, it is not advisable to use medication blindly on your own. It is recommended that you consult a doctor in a regular hospital and follow the doctor’s advice to use the medication on time.