Is influenza A or B more likely to cause high fever or low fever?

Influenza A and Influenza B are two forms of influenza, known as Type A and Type B flu respectively. Although they share common symptoms, they differ significantly in their pathogenesis. Influenza A is a relatively severe epidemic infectious disease primarily caused by the Influenza A virus. Its main symptoms include high fever, headache, muscle aches, fatigue, coughing, and so on. Viral infection may lead to pneumonia or lung complications, and can also trigger other manifestations such as cardiovascular, neurological, and liver disorders. In contrast, Influenza B is caused by the Influenza B virus, with primary symptoms including fever, headache, mild muscle aches, general fatigue, runny nose, and cough. The fever in Influenza B typically ranges between 37–38 °C, lower than the high fever seen in Influenza A, and the illness is generally milder with no serious threat to human health. Therefore, Influenza A is considered a high-fever illness, whereas Influenza B is mainly characterized by low-grade fever and is less harmful than Influenza A. Based on specific clinical presentations, doctors should provide the most appropriate diagnosis and treatment plan.