What should you know about a virus that causes fever for five days?

Fever reflects the body’s response to infection and can accompany respiratory, gastrointestinal or other illnesses. [COVID-19](/conditions/covid-19/), [Common Cold](/conditions/common-cold/) and [Acute Bronchitis](/conditions/acute-bronchitis/) can include fever, but the duration alone cannot identify the infection. Other possibilities include a bacterial infection, inflammation or a medicine reaction. A clinician will consider age, temperature pattern, hydration, breathing, pain, travel and examination findings.

Arrange a medical assessment rather than relying on the number of days alone. Drink regularly, rest, wear light clothing and record temperature readings, medicines and new symptoms. Use fever medicine only as directed for the person’s age and health; do not combine products that contain the same ingredient. Keep distance from vulnerable people while an infectious cause is possible and follow local clinical advice.

Seek urgent help for breathing difficulty, chest pain, confusion, a seizure, severe headache with a stiff neck, a non-blanching rash, fainting, or inability to keep fluids down. Children who are hard to wake, have markedly reduced urine, or are working hard to breathe need urgent assessment. Prompt review is also needed for worsening focal pain, repeated vomiting or fever that continues despite improving other symptoms.

Ask what examination or tests may clarify the cause, how to monitor hydration, and which changes should prompt emergency care. Mention cough, noisy breathing or wheeze; [Bronchiolitis](/conditions/bronchiolitis/) and [Croup](/conditions/croup/) are examples of illnesses where breathing symptoms matter.