The 2009 H1N1 influenza is a type of flu. Like any flu, it mainly affects the lungs. It is caused by a strain of influenza A called H1N1, which was discovered in 2009. The 2009 H1N1 flu is sometimes called swine flu because scientists originally thought the virus came from pigs (swine). But it is now known that this is not the case and that the germ is a new virus. This sheet answers some questions you may have about the 2009 H1N1 flu.
The 2009 H1N1 flu virus can spread easily among people the same way the regular flu spreads—through the air in droplets when someone with the virus coughs, sneezes, laughs, or talks. You can also become infected when you touch a surface on which the droplets have landed and then transfer the virus to your eyes, nose, or mouth. Touching used tissues, or sharing utensils, drinking glasses, or a toothbrush with an infected person can expose you to the 2009 H1N1 flu virus, too.
Note: 2009 H1N1 flu is not caused by eating pork or pork products. Eating pork or pork products that have been properly handled and cooked is safe.
2009 H1N1 flu symptoms are about the same as regular flu symptoms. These include:
Fever, usually higher than 100.4°F (38°C), and chills
Body and muscle aches
Tiredness and weakness
Diarrhea and vomiting
Call your healthcare provider for advice if any of the above symptoms become severe. If 2009 H1N1 flu is in your area, your healthcare provider may have you tested.
Most people who come down with influenza get better on their own. This includes people infected with 2009 H1N1 flu. If your symptoms are severe, your healthcare provider may prescribe medicines called antivirals. These medicines can reduce the severity and length of illness, but only if they are taken within 2 days of when your symptoms started. The medicines do not guarantee that you will avoid feeling sick, and they will not help much with mild illness. Note that antibiotics are not helpful against influenza.
If your symptoms are mild, your healthcare provider will likely tell you to follow the self-care measures listed below.
Unless told otherwise by your doctor, drink plenty of nonalcoholic fluids, such as water or juice, to prevent dehydration. A good rule is to drink enough so that you urinate your normal amount.
Get plenty of rest.
Ask your healthcare provider about acetaminophen or other medicines for fever and pain. Take any medicine only as directed. Do not give aspirin to children under age 18. It can cause a rare but serious illness called Reye syndrome.
Call your doctor if your fever is 100.4°F (38°C) or higher, or you become dizzy, lightheaded, or short of breath.
Wash your hands often, especially after coughing or sneezing. Or clean your hands with an alcohol-based hand gel containing at least 60% alcohol.
Cough or sneeze into a tissue. Then throw the tissue away and wash your hands. If you don’t have a tissue, cough or sneeze into the crook of your elbow.
Stay home until at least 24 hours after you no longer have a fever or fever symptoms (such as chills), and you are not taking fever-reducing medicine.
Don’t share food, utensils, drinking glasses, or a toothbrush with others.
You can use a medical facemask over your mouth and nose to help prevent spread of infected droplets when you cough, sneeze, laugh, or talk. You should still follow the measures listed above to decrease your chance of spreading the virus to others.
Ask your doctor whether others in your household should get antiviral medicine to help them avoid infection.
One of the best ways to prevent the 2009 H1N1 flu is to get vaccinated. Each year, a vaccine is designed to protect against the main types (strains) of influenza that are making people sick. For several years after 2009, the yearly flu vaccine has protected against the 2009 H1N1 flu virus, as well as two other flu viruses. Most often, the vaccine is given as a shot. But some people may get the vaccine in nasal spray form instead. Your doctor can tell you which vaccine is right for you. The nasal spray is not recommended for the 2016-2017 flu season. The CDC says this is because the nasal spray did not seem to protect against the flu over the last several flu seasons. In the past, it was meant for people ages 2 to 49.
Wash your hands often. Frequent handwashing is a proven way to prevent infection.
Carry an alcohol-based hand gel containing at least 60% alcohol. Use it when you can't use soap and water. Alcohol gels kill most germs and are safe for children.
Avoid touching your eyes, nose, and mouth.
At home and work, clean phones, computer keyboards, and toys often with disinfectant wipes.
If possible, avoid close contact with others, especially if 2009 H1N1 flu cases have been identified in the area where you live or work.
Handwashing is one of the best ways to prevent the spread of 2009 H1N1 flu and other common infections. Follow these steps:
Use warm water and plenty of soap. Work up a good lather.
Clean the whole hand, under your nails, between your fingers, and up the wrists.
Wash for at least 15 seconds. Don’t just wipe—scrub well.
Rinse, letting the water run down your fingers, not up your wrists.
Dry your hands well. Use a paper towel to turn off the faucet and open the door.
Alcohol-based hand gels are also a good choice for cleaning your hands. Use them when you don’t have access to soap and water, or your hands aren’t visibly dirty. Follow these steps:
Squeeze about a teaspoon of gel into the palm of one hand.
Rub your hands together briskly, cleaning the backs of your hands, the palms, between your fingers, and up the wrists.
Rub until the gel is gone and your hands are completely dry.
Call your healthcare provider right away if you have any of the following:
Fever of 100.4°F (38°C) or higher, or as directed by your healthcare provider
Dizziness or lightheadedness
Trouble breathing, shortness of breath, or chest pain or pressure
Cough with lots of colored sputum (mucus) or blood in the sputum
Severe headache, or face, neck, or ear pain
Confusion, behavior change, or seizure
Severe or repeated vomiting or inability to keep fluids down
Visit the CDC website: