Influenza is a symptom of the body being infected with the influenza virus that causes the acute respiratory system. Symptoms include sudden high fever, headache, body aches, and fatigue. flu symptoms For those who are sick with influenza When symptoms appear, they usually occur immediately and
7 groups at risk for influenza Groups that have a higher chance of complications and danger than the general population are called high-risk groups , which include: Complications of influenza The most common complications of influenza include otitis media, sinusitis, and bronchitis. More severe complications include pneumonia or pneumonia.