In young children with influenza, i.e., the flu, the fever does not necessarily last for a week. If there are no complications, the fever will usually subside after 3 to 4 days, but if there are complications such as pneumonia, the fever may last a week or even longer. Influenza is an acute respiratory infectious disease caused by influenza virus infection. Clinical manifestations include fever, headache, myalgia, general malaise, dry cough, nasal congestion, runny nose, chills, chills, loss of appetite, fatigue, sore throat and other symptoms. Influenza without complications, can be self-limiting, mostly 3 to 4 days after the onset of fever gradually subside, systemic symptoms tend to improve, but physical strength and cough recovery often need a longer period of time. Influenza can be complicated by pneumonia, cardiac injury, neurological injury, rhabdomyolysis, septic shock and other diseases, the course of the disease will be prolonged, the fever may also last a week, or even longer. If a young child has an influenza fever, he or she should seek early medical attention to avoid delaying the illness.