Whether a child has influenza should be judged from clinical manifestations and laboratory tests. 1. Clinical manifestations: incubation period of 1~3 days, with obvious epidemic and outbreak. It is divided into simple type, gastrointestinal type, pneumonia type and poisoning type. (1) Simple type: the onset of the disease is rapid, with chills, high fever, dizziness, headache, generalized pain and fatigue and other toxic manifestations. (2) Gastrointestinal type: accompanied by gastrointestinal symptoms such as abdominal pain, bloating and diarrhea. (3) Pneumonia type: manifestations of pneumonia, such as high fever, chills, cough, sputum, chest tightness, shortness of breath, dyspnea, headache, generalized muscle pain, fatigue, and even respiratory failure may occur. (4) Poisoning type: systemic toxemia, which may lead to shock, disseminated intravascular coagulation, or even death. 2. Laboratory examination: relative increase of peripheral blood lymphocytes, isolation of influenza virus in nasopharyngeal and lower respiratory secretions, and positive influenza virus antigen in respiratory epithelial cells. If you find that your child has the above clinical manifestations, you should take your child to the hospital for examination and treatment under the guidance of a doctor.