What Is Swine Flu?

The H1N1 flu, often called "swine flu," first appeared in the U.S. in April 2009 and quickly went on to become a pandemic, which means it was seen worldwide. H1N1 spreads between people, not pigs. The "swine flu" nickname comes from the way the virus evolved, as a mix of genes from swine, bird, and human viruses. By August 2010, the pandemic was over, but experts believe H1H1 will continue to hang around for several flu seasons.

Swine Flu Virus

Here is a picture of the 2009 H1N1 swine flu virus, colorized and magnified.

What Are Swine Flu Symptoms?

Symptoms of H1N1 swine flu are like regular flu symptoms and include fever, cough, sore throat, body aches, headache, chills, and fatigue. Some people have reported diarrhea and vomiting associated with swine flu. Those symptoms can also be caused by many other conditions, and that means that you and your doctor can't know, just based on your symptoms, if you've got swine flu. It takes a lab test to tell whether it's swine flu or some other condition.

When Should I See My Doctor?

If you only have mild flu symptoms and you're not at high risk of severe disease, you don't need medical attention unless your illness worsens. If you are at high risk (pregnant women, young children, people with chronic medical conditions such as asthma, and elderly people), call or email your doctor at the first sign of flu-like symptoms.

When Is Swine Flu an Emergency?

Children should get urgent medical attention if they have fast breathing or trouble breathing, have bluish or gray skin color, are not drinking enough fluid, are not waking up or not interacting, have severe or persistent vomiting, are so irritable that the child doesn't want to be held, have flu-like symptoms that improve but then return with fever and a worse cough, have fever with a rash, or have fever and then have a seizure or sudden mental or behavioral change. Adults should seek urgent medical attention if they have trouble breathing or shortness of breath, pain or pressure in the chest or abdomen, sudden dizziness, confusion, severe or persistent vomiting, or flu-like symptoms that improve, but then come back with worsening fever or cough.

How Does Swine Flu Spread?

The 2009 H1N1 swine flu virus spreads just like regular flu. You could pick up germs directly from an infected person, or by touching an object they recently touched, and then touching your eyes, mouth, or nose, delivering their germs for your own infection. That's why you should make a habit of washing your hands, even when you're not ill. Flu germs can start spreading up to a day before symptoms start, and for up to seven days after getting sick, according to the CDC.

How Is Swine Flu Treated?

The 2009 H1N1 swine flu virus is sensitive to the antiviral drugs Tamiflu and Relenza. But not everyone needs those drugs. Most people who have come down with swine flu have recovered without treatment. The CDC has recommended prioritizing antiviral drugs for people with more severe flu illness and people in high-risk groups.

Is There a Swine Flu Vaccine?

Yes. WebMD Senior Writer Dan DeNoon, pictured here, took part in a trial of the H1N1 vaccine. Swine flu came on the scene too late in 2009 to be included in the regular flu shot that people can get beginning in October each year. For winter 2010-2011, the H1N1 vaccine was included in the seasonal flu vaccine. It comes as a shot or nasal spray.

How Severe Is Swine Flu?

The severity of cases has varied widely, from mild cases to fatalities. Most U.S. cases have been mild, but there have been a number of deaths and hospitalizations. Flu viruses can change, and it's impossible to know whether the 2009 H1N1 swine flu virus will become more deadly. But so far, this particular virus hasn't changed much since it first appeared.

How can I prevent swine flu infection?

The CDC recommends taking these steps:

• Wash your hands regularly with soap and water, especially after coughing or sneezing. Or, use an alcohol-based hand cleaner.
• Avoid close contact with sick people.
• Avoid touching your mouth, nose, or eyes.

Got flu symptoms? Stay home, and when you cough or sneeze, cover your mouth and nose with a tissue. Afterward, throw the tissue in the trash and wash your hands.

What Else Should I Be Doing?

Keep informed of what's going on in your community. Your state and local health departments will have important information on how your area is handling flu.

Can I Still Eat Pork?

The nickname "swine flu" initially caused a lot of confusion and some worries about what was safe to eat. The answer is "yes," pork is safe to eat. You can't get swine flu by eating pork, bacon, or other foods that came from pigs.

More Reading on Swine Flu

• Swine Flu (Swine Influenza A (H1N1) Virus)
• Swine Flu FAQ
• Swine Flu: How a Hospital Prepares for Patients
• How Does a Person Catch Swine Flu?
• Dr. Smith's Swine Flu Q & A
• Read the Latest Swine Flu News