Influenza (Flu) | CDC
Skip directly to site content
Skip directly to search
An official website of the United States government
Here's how you know
Official websites use .gov
.gov
website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
lock
) or
means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.
Influenza (Flu)
Signs and Symptoms
Learn about identifying flu symptoms, how the diagnosis works, common complications, and more.
Aug. 26, 2024
For Everyone
Prevention
Strategies to reduce the risk of seasonal flu.
Sept. 26, 2025
Flu Treatment
If you get sick with flu, flu antiviral drugs may be a treatment option.
Sept. 2, 2025
A(H5) Bird Flu: Current Situation
A(H5) bird flu is causing outbreaks in wild birds and poultry, other animals and sporadic human case
Weekly U.S. Influenza Surveillance Report
Respiratory Illnesses
Learn what respiratory illnesses have in common and steps to help protect yourself and others.
About Estimated Flu Burden
Each year, CDC estimates the burden of flu in the U.S to understand the impact of flu each season
FluVaxView
Flu vaccination data for people 6 months and older as recommended by the ACIP.
Featured
Influenza for Health Care Providers
Health care professionals play a critical role in helping patients choose flu vaccines.
Sept. 3, 2024
About
Flu is a contagious respiratory illness that infect the nose, throat, and sometimes the lungs.
Aug. 13, 2024
Information for the Flu Season
Learn about the current flu season and find resources related to flu surveillance and past seasons.
Aug. 31, 2022
Flu Complications and People at Higher Risk
Learn more about who is at higher risk of developing potentially serious flu complications.
Sept. 11, 2024
Flu Resource Center
Access CDC communication resources to share information about the importance annual flu vaccination
Aug. 14, 2024
Similarities and Differences between Flu and COVID-19
Learn about prevention and treatment for flu and COVID-19.
Sept. 17, 2024
What's New
View More
Influenza (Flu)
Influenza (flu) is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and lungs.
View All
For Everyone
About
Signs and Symptoms
Causes and Spread
Flu Complications and People at Higher Risk
Prevention
Vaccine Basics
Diagnosis
Flu Treatment
View all
Health Care Providers
Clinical Guidance
Clinical Signs and Symptoms of Influenza
Guidance for Influenza Vaccination
View All
Public Health
How CDC Classifies Flu Severity each Season in the United States
Information for Laboratories
Understanding Influenza Viruses
View All
Sign up for Email Updates