H1N1 flu (swine flu): How serious is the global threat?

Q: What's the real story about swine flu? I've heard it called a pandemic, but I'm not sure what that means.

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You're not alone in your confusion about swine flu — specifically, the flu caused by novel swine influenza H1N1 virus, which was identified and designated a global pandemic in spring 2009. Because this is a new flu virus, everyone is vulnerable to infection.

Swine flu is one of the many type A influenza viruses. It's unusual for humans to catch swine flu, but occasional cases occur, usually in people who have contact with infected pigs. Like other flu viruses, the swine flu virus changes its DNA as it spreads, giving rise to a number of subtypes.

A new vaccine has been developed to protect against H1N1 swine flu. To reduce your risk of catching and spreading the virus:

• Keep tabs on respiratory symptoms. If you or someone in your family develops symptoms suggesting a cold or the flu, avoid crowds, and be alert for persistent or worsening symptoms, particularly a high fever.
• Stay home if you're sick. If you have swine flu or seasonal flu, don't go to work, school or public gatherings until you've had no fever and taken no fever-reducing medication for 24 hours. Unless your infection is unusually severe, fever and other symptoms should end in three to five days.
• Wash your hands thoroughly and frequently. Flu viruses can survive for two hours or longer on surfaces, such as doorknobs and countertops.
• Be prepared. Ask your health care provider or county health department about immunization and infection-control plans.