Why is there no fever when infected with influenza B?

　　Influenza B usually refers to Influenza B. Generally speaking, the main reasons for being infected with Influenza B without developing a fever include strong immunity, low viral load, low baseline body temperature, immunosuppressive status, and early stages of the disease. If symptoms occur, it is recommended to seek timely diagnosis and treatment at a regular hospital. The detailed analysis is as follows:

　　1. Strong immunity

　　The body's immune system can quickly recognize and eliminate the Influenza B virus without triggering an obvious fever response. In daily life, one should maintain regular作息, ensure sufficient sleep, and consume more fresh fruits and vegetables rich in vitamin C, such as oranges and broccoli, to maintain stable immune function.

　　2. Low viral load

　　A small amount of Influenza B virus was contracted, and the immune system can control viral replication without inducing a strong fever response. At this time, attention should be paid to rest, drinking plenty of warm water to help eliminate the virus, and avoiding crowded places to prevent virus spread.

　　3. Low baseline body temperature

　　Some people naturally have a lower baseline body temperature, so even if their temperature rises slightly after contracting Influenza B, it does not reach the conventional fever threshold. Regular monitoring of temperature changes and recording fluctuations can help doctors assess the condition.

　　4. Immunosuppressive status

　　Conditions such as systemic lupus erythematosus, rheumatoid arthritis, or long-term use of immunosuppressive drugs can weaken the body's immune response, potentially preventing the onset of fever after Influenza B infection. Patients should follow medical advice to use medications such as methylprednisolone tablets, leflunomide tablets, and cyclosporine soft capsules to manage underlying conditions, while taking additional precautions to avoid repeated infections.

　　5. Early stages of the disease

　　After infection with Influenza B, the virus has not yet multiplied extensively in the body, and the inflammatory response is mild, so fever symptoms have not yet appeared. Close observation of physical condition is advised, and if symptoms such as sore throat or cough occur, medications like Lianhua Qingwen capsules, Jinhua Qinggan granules, or Shufeng Jiedu capsules may be used under medical guidance to alleviate discomfort.

　　In daily life, attention should be paid to frequent handwashing to maintain hand hygiene, regular indoor ventilation for better air circulation, avoiding contact with Influenza B patients as much as possible, wearing masks when necessary, and engaging in appropriate physical exercise to enhance resistance.