The duration of fever from influenza A is closely related to the severity of the disease and your immunity, so the length of fever may vary and cannot be generalized. Influenza A is an acute respiratory infection caused by the influenza A virus, which is prevalent in winter and spring. Usually, influenza A fever lasts for 2-7 days and is accompanied by dizziness, headache, runny nose and other symptoms. The duration of fever varies from patient to patient because of the different body types and degrees of illness, which can affect the resistance to the virus. If a patient has a fever, it is recommended to go to the respiratory department of a hospital in a timely manner and take medication under the guidance of a doctor.