Seasonal Flu

In the United States, "regular" seasonal flu season usually occurs between November and April. Seasonal flu is a viral infection of the respiratory tract (nose, throat, bronchial tubes, and lungs) that can be transmitted easily from person to person. Most people get better without problems. But sometimes the flu can lead to a secondary infection, such as an ear infection, a sinus infection, or bronchitis. In rare cases, the flu may cause a more serious problem, such as pneumonia.

Certain people are at higher risk of problems from the flu

They include:

• pregnant women
• young children 
• older adults
• people with long-term illnesses or with impaired immune systems that make it hard to fight infection.

Seasonal flu epidemics typically cause illness in 5% to 20% of people and, though most are able to recover without problems, the seasonal flu viruses are associated with an average of 36,000 deaths and 200,000 hospitalizations in the U.S. each year.

Even if most people have some immunity to seasonal flu, getting an annual flu vaccine is the best way to prevent getting the flu. Flu vaccination is especially important for people at high risk for serious flu complications, including pneumomia.