Fever after influenza vaccination usually resolves itself within 2-3 days, but the exact recovery time varies from person to person. Fever after influenza vaccination is usually a normal immune response, and most of the fever will subside within 2-3 days after vaccination and does not require special treatment. In order to relieve the discomfort caused by fever, if the fever is within 38.5℃, physical cooling can be used, such as the use of fever-reducing patches; if the fever exceeds 38.5℃, antipyretic drugs can be used as prescribed by the doctor. However, if there is infection at the vaccination site, the fever may worsen and the duration of fever may be prolonged. After vaccination, you need to stay in the hospital for half an hour for observation and then leave if there is no abnormality. Do not be alarmed if you develop a fever. Rest and keep the vaccination site clean and dry. If you have a high fever (temperature over 39℃) that does not go away, you should consult a fever clinic or emergency department.