Influenza (commonly called the “flu”) is a contagious respiratory illness caused by viruses. The flu is a serious medical problem, hospitalizing more than 200,00 American annually.

The Centers for Disease Control (CDC) offers Seasonal Flu website. You can learn Flu Basics, Preventing the Flu, and What to do if you Get Sick. The CDC also publishes a weekly flu map..

The U.S. Department of Health and Human Services, through it's Medicare Division offers Flu Information. There is information available, specific to getting flu shots..

GovGab offers some pros and cons about getting a flu shot. You can read how CDC scientists select the viruses that are in the flu vaccine.

Thomas Jefferson University offers a detailed web resource on the flu. Topics discussed include causes of influenza, cold versus flu symptoms, prevention, vaccine information, and treatment of the flu.