Seasonal epidemics occur yearly in the fall and winter months.
Influenza is very contagious, and anyone can become infected. Influenza spreads easily from person to person when an infected person coughs or sneezes. The flu virus can also survive on surfaces outside the human body for hours. People might become infected by getting the virus on their hands and then rubbing their eyes or nose. Typical symptoms include high fever, cough, sore throat, runny or stuffy nose, headache, muscle aches, and often extreme fatigue.