Influenza: How to prevent and treat a serious infection

It happens every year. The days grow shorter, the temperature drops — and the flu strikes. Influenza is so common that it's easy to dismiss this seasonal affliction as "just a virus" or "just the flu." It's true that the flu is caused by a virus and that most people recover without any therapy other than rest. But it's also true that thousands of Americans die from the flu each year, and millions are sick enough to miss work or school. Influenza is a serious infection — but it can be prevented and treated.

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Special features

	HealthMap Flu Vaccine Finder HealthMap Vaccine Finder is a free service that allows users to search for flu vaccines based on their location. Powered by Harvard Medical School and Boston Children's Hospital. Go to HealthMap »
	How an influenza virus infects a cell See how a flu virus enters a healthy cell, replicates, and exits with this narrated, step-through animation. View slideshow »
	Herd immunity Vaccination protects individuals from disease, but it can also benefit an entire community by protecting even those few who are not vaccinated. The phenomenon is known as herd immunity See how it works. View slideshow »

Learn more about the flu virus and how to protect yourself

• When to contact your doctor about flu symptoms


• 10 flu myths


• How to boost your immune system


• Handwashing tips


• Vaccines and your health


• Recommended adult vaccinations

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