Influenza (flu) is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness. Serious outcomes of flu infection can result in hospitalization or death. Some people, such as older people, young children, and people with certain health conditions, are at high risk of serious flu complications. There are two main types of influenza (flu) virus: Types A and B. The influenza A and B viruses that routinely spread in people (human influenza viruses) are responsible for seasonal flu epidemics each year.
The best way to prevent flu is by getting vaccinated each year.
Seasonal Influenza (Flu) Information
Centers for Disease Controlnew window (CDC)
Montgomery County Department of Health and Human Servicesnew window
Flu & You (PDF, ) (CDC)
Key Facts about Influenzanew window (CDC)
How Flu Spreadsnew window (CDC)
Key Facts About Seasonal Flu Vaccinenew window (CDC)
A Strong Defense Against the Flu (PDF, ) (CDC)
Poster: Everyday Preventive Actions (PDF, ) (CDC)