To determine whether a child’s fever is influenza, the main combination of epidemiologic history, clinical manifestations, and pathogenetic examination. 1. Epidemiologic history: If there is an epidemiologic history of influenza in the current surroundings, and the child has had close contact with a suspected or confirmed influenza patient within 7 days before the onset of fever without effective personal protection. 2. Clinical manifestations: the child has typical influenza symptoms, such as high fever, dehydration, headache, vomiting and diarrhea. 3. Pathogenetic examination: Positive nucleic acid test of influenza virus, positive culture isolation of influenza virus, positive test of influenza antigen, etc. Positive results of one or more of these tests can generally confirm the diagnosis of influenza. If a child has any of the above conditions, it is important to consult a doctor in a timely manner and cooperate with him or her in taking examinations and treatments.