Swine Flu (H1N1)

Swine flu (H1N1) is a type of viral infection. It’s called swine flu because it resembles a respiratory infection that pigs can get. In 2009, an H1N1 pandemic infected millions of people worldwide. Today, you can prevent H1N1 with an annual flu shot. You can treat it with rest, fluids and antiviral medications.


What is swine flu (H1N1)?

Swine flu (H1N1) is an infection that a type of flu (influenza) virus causes. It’s called swine flu because it’s similar to a flu virus that affects pigs (swine). The virus leads to a lung (respiratory) disease in pigs. Swine flu (H1N1) is a respiratory infection in humans.


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Are swine flu (H1N1) and Spanish flu the same thing?

In 1918, a flu pandemic from a strain of H1N1 infected 500 million people around the world. It was known as the Spanish flu. At least 50 million people worldwide died.

Where did the 2009 swine flu (H1N1) pandemic start?

In April 2009, researchers discovered a new strain of H1N1. They detected it in the United States first. The virus spread quickly across the U.S. and around the world. It spread quickly because it was a new type of flu virus.

Young people weren’t immune to the new virus yet. Older people appeared to have some immunity to the virus. They may have had exposure to an older strain of H1N1 that helped protect them.

The new strain infected millions of people worldwide. At least 150,000 people worldwide died. Eighty percent of those who died were younger than 65.


When did the swine flu (H1N1) pandemic end?

The World Health Organization (WHO) said the pandemic was over in August 2010. However, people can still get and spread H1N1. H1N1 is one of the seasonal flu viruses. It can cause illness, hospitalization and death.

Symptoms and Causes

What causes swine flu (H1N1)?

A virus causes swine flu (H1N1). It spreads from person to person. When a person coughs or sneezes, droplets go into the air. You can get the infection when you breathe in (inhale) the virus. You can also get the infection when you touch a contaminated surface and then touch your mouth, nose or eyes.

You can’t get H1N1 by eating pork.


Is swine flu (H1N1) contagious?

Yes. Swine flu (H1N1) is contagious. It can spread from person to person.

What are the symptoms of swine flu (H1N1)?

The symptoms of swine flu (H1N1) are similar to the symptoms of regular flu. The symptoms may start three to five days after exposure to the virus. Symptoms may include:

Symptoms in babies and children may be different. If your baby or child has any of the following symptoms, call their healthcare provider right away:

  • Trouble breathing.
  • Trouble waking up.
  • Not drinking enough fluids.
  • Fever with rash.
  • Confusion.

Diagnosis and Tests

How is swine flu (H1N1) diagnosed?

Your healthcare provider can diagnose swine flu (H1N1). They may perform a physical exam and ask you about your symptoms. Your provider may order a rapid flu test. A rapid flu test checks for several different flu viruses. It may take a few days to get the H1N1 test results back.

Management and Treatment

How is swine flu (H1N1) treated?

Most people with swine flu (H1N1) who are otherwise healthy don’t need special drugs or treatments. If you have swine flu, you should:

  • Get plenty of rest.
  • Drink fluids.
  • Eat a light diet.
  • Stay home.
  • Take acetaminophen (Tylenol®) to reduce fever and relieve aches and pains.

If you’re very ill, your healthcare provider may prescribe an antiviral medicine. Antiviral drugs such as oseltamivir (Tamiflu®) or zanamivir (Relenza®) can kill the virus. These drugs can shorten the time you’re sick and help ease your symptoms. Antiviral drugs work best if you start taking them when your symptoms begin.


How is swine flu (H1N1) prevented?

The best way to prevent swine flu (H1N1) is to get your annual flu vaccine. The flu vaccine has helped protect against swine flu since 2010.

Other ways to prevent getting and spreading swine flu (H1N1) include:

  • Cover your nose and mouth with a tissue when you sneeze or cough.
  • If you don’t have a tissue, sneeze or cough into your elbow.
  • Wash your hands with soap and water.
  • Don’t touch your eyes, nose or mouth.
  • Avoid people who are sick.
  • Stay home if you're sick.
  • Don’t share personal items such as cups, straws and utensils.

Living With

When should I see my healthcare provider?

Most people can fight off swine flu (H1N1) on their own. The symptoms of H1N1 are similar to those of regular flu. On average, symptoms last about eight days. Call your healthcare provider if your symptoms last longer or worsen. They’ll let you know if you should come in to the office. They may have you take a rapid flu test to see if you have H1N1.

What questions should I ask my healthcare provider?

  • Who should get the flu vaccine?
  • When should I get the flu vaccine?
  • How can I tell the difference between a cold and the flu?
  • How long do I need to take antiviral medicine to treat swine flu?
  • When can I go back to work or school if I’ve had swine flu?

A note from Cleveland Clinic

Swine flu (H1N1) once caused a serious worldwide pandemic. Today, the virus is under control, but people can and do still get very sick from H1N1. It’s important to get your yearly flu shot, which can protect you from H1N1 and other strains of the flu. If you do get sick, make sure to get plenty of rest, drink fluids and call your healthcare provider if symptoms worsen.

Medically Reviewed

Last reviewed on 08/05/2022.

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