Reviewed by Christopher A Czaja
The 2009 H1N1 flu was first identified in the United States in April, 2009.

H1N1 (initially known as the swine flu) is an infection of the respiratory system that is caused by the H1N1 virus. The swine flu virus normally infects pigs, but rarely infects humans. A variation of the swine flu virus, the H1N1 virus, does spread from human to human through coughing or sneezing by a person with H1N1 flu. How easily the H1N1 is spread from human to human is currently being investigated.

Read an update on the the upcoming influenza season and the current H1N1 pandemic.



The CDC recommends that vaccination efforts should first focus on people in five target groups.

  • Pregnant women,

  • People who live with or provide care for infants younger than 6 months (e.g., parents, siblings, and day care providers),

  • healthcare and emergency medical services personnel,

  • People 6 months through 24 years of age, and,

  • People 25 years through 64 years of age who have certain medical conditions that put them at higher risk for influenza-related complications, including asthma, emphysema, and certain immune disorders.

Find a clinic that offers the seasonal and H1N1 vaccines.



Symptoms of the 2009 H1N1 Flu are somewhat similar to those of seasonal flu. Symptoms typically begin very quickly.

Symptoms often include:

  • Body aches,

  • Feeling very tired,

  • Fever and/or chills,

  • Headache,

  • Cough,

  • Sore throat and

  • Runny nose.

Diarrhea and vomiting have also been seen with the 2009 H1N1 Flu. In addition, children may also have a high fever, diarrhea and seizures. The severity and course of the symptoms and populations at risk for severe symptoms are still being investigated. 



What you can do to stay healthy:

  • Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it.

  • Wash your hands often with soap and water, especially after you cough or sneeze. Alcohol-based hands cleaners are also effective.

  • Avoid touching your eyes, nose or mouth. Germs spread that way.

  • Avoid close contact with other people with flu-like symptoms.

  • If you are sick, stay home for 7 days after your symptoms begin or until you have been symptom-free for 24 hours, whichever is longer. This is to keep from infecting others and spreading the virus further.


If You Get Sick

If you are not in a high-risk group and have mild symptoms, stay home for 7 days after your symptoms begin or until you have been symptom-free for 24 hours, whichever is longer. This is to keep from infecting others and spreading the virus further.

If you are in a high-risk group or have severe symptoms (listed below), contact your primary care physician or go to an emergency room.

Treatment with antiviral medicine is available when someone gets the 2009 H1N1 Flu. These medicines help lessen the symptoms and the length of time a person is ill. Antiviral medicines must be started within the first two days after symptoms begin.

These medicines include:

  • Relenza® (zanamivir)
  • Tamiflu® (oseltamivir)

Severe Signs and Symptoms

In children, signs that urgent medical attention is needed include:

  • Fast breathing or trouble breathing
  • Bluish or gray skin color
  • Not drinking enough fluids
  • Severe or persistent vomiting,
  • Not waking up or not interacting
  • Being so irritable that the child does not want to be held
  • Flu-like symptoms improve but then return with fever and worse cough

In adults, signs that urgent medical attention is needed include:

  • Difficulty breathing or shortness of breath
  • Pain or pressure in the chest or abdomen
  • Sudden dizziness
  • Confusion
  • Severe or persistent vomiting
  • Flu-like symptoms that improve, then return with a fever a worsening cough.


More Information

For the latest information on 2009 H1N1 Flu, visit the CDC website.

For Kids
Scrub Club®: A fun, interactive and educational website that teaches children the proper way to wash their hands (American Red Cross).

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