HowStuffWorks explains that influenza is contagious for about five to seven days following the onset of symptoms. However, it is important to understand that people are often contagious for about 24 hours prior to the onset of symptoms. However, children remain contagious for much longer. They may continue to spread the virus for up to two weeks after the appearance of symptoms or even after their symptoms subside.
According to the New York State Department of Health, the influenza virus is spread through the coughs and sneezes of an infected person. If individuals swallow or breathe in these infected droplets, they may become infected by the virus. Additionally, some people may contract the illness by touching an inanimate object that has the virus on it before then touching their eyes, nose or mouth.
The primary symptoms of the flu include a fever, sore throat, cough, nasal congestion, headaches, body aches and fatigue, according to the New York State Department of Health. As explained by HowStuffWorks, some of these symptoms, such as a sore throat, are caused by the virus itself. Conversely, the fatigue and fever are symptoms produced by the body as it attempts to fight off the infection.
According to the New York State Department of Health, approximately 200,000 people are hospitalized each year in the United States due to influenza. Approximately 23,000 of these people, primarily those over the age of 65, die each year.