Headache after vaccination may be related to adverse reactions, own disease factors and so on. 1. If headache occurs after vaccination, it is firstly considered to be caused by the adverse reaction of the vaccine. Due to allergy to the components of the vaccine, adverse reactions can occur, and some vaccinated people may also be accompanied by nausea and vomiting and other symptoms. However, the degree of symptoms is usually relatively mild and can be relieved on their own. If the symptoms continue to be unrelieved or aggravated, it is necessary to consult a doctor in time. 2. But do not rule out the possibility of their own disease caused by such manifestations, such as colds, cerebrovascular disease, etc., may also appear headache symptoms. Such symptoms appear after vaccination and may be mistaken for adverse reactions to vaccines. It is necessary to consult a doctor in a timely manner, under the guidance of the doctor for blood tests, brain CT and other tests, to determine the cause of the disease and then take targeted treatment.