Influenza A H3N2 may have fever (some may have high fever, up to 39~40℃), accompanied by chills, chills, headache, muscle aches, fatigue, loss of appetite and other systemic symptoms, but also sore throat, cough, nasal congestion, runny nose and other respiratory symptoms. Mild influenza is often similar to the symptoms of the common cold and is not easy to distinguish, but the fever and systemic symptoms of influenza are more obvious. Severe influenza can present with viral pneumonia, secondary bacterial pneumonia, acute respiratory distress syndrome, shock and even death. Severe influenza mainly occurs in the elderly, young children, pregnant women or people with chronic underlying diseases, but can also occur in the general population. Influenza vaccination is currently the most effective means of preventing influenza. It is also important to develop good personal hygiene habits, including: washing hands frequently and not touching eyes, mouth and nose with hands; avoiding places where people gather; and avoiding close contact with family members when they have influenza. If you have any of the above symptoms, you should seek medical attention as soon as possible and be treated under the guidance of your doctor.