Influenza (flu) is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and lungs. Learn about flu, including symptoms, prevention methods, and treatment options.

Jan 7, 2026 · Flu cases and hospitalizations are surging, already breaking last season's records. Here's where activity is highest, what symptoms to watch for and how to protect yourself.

Jan 8, 2026 · View data by activity level includes illnesses associated with COVID-19, influenza, RSV (respiratory syncytial virus), and general respiratory illnesses, such as cough or sore throat.

Dec 19, 2025 · Flu, also called influenza, is an infection of the nose, throat and lungs, which are part of the respiratory system. The flu is caused by a virus. Influenza viruses are different from the "stomach …

3 days ago · Why are some flu seasons worse than others? The variation in incidence is a function of a couple of things. The first is how much of the population is susceptible to the circulating strain of …

What is the flu (influenza)? The flu is an illness you get from the influenza virus. It causes symptoms like head and body aches, sore throat, fever and respiratory symptoms, which can be severe. Flu is most …

Jan 9, 2026 · Flu activity continues to remain elevated in the United States, according to newly released data from the Centers for Disease Control and Prevention.

4 days ago · This year's flu season is shaping up to be particularly brutal. Here's what to know this week, including cases taking a downturn.

3 days ago · Infectious disease doctors explain why the flu is striking so hard and how to prevent and manage the illness.

15 hours ago · California officials warn of an increase in flu-related hospitalizations and confirm a second severe-flu-related death.