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Protect Yourself Against H3N2v

Understanding the nature of flu (influenza) viruses and how to prevent infection is the best way to lower your chance of getting sick from H3N2v virus.


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Video Podcast: CDC Recommendations to Reduce the Risk of H3N2v Flu Virus Infection for Fairgoers and Swine Exhibitors [5 MB, 5 min 51 sec]


What is H3N2v?

H3N2v is a virus that usually infects pigs but not people.  This virus is very different from human seasonal H3N2 viruses.  A number of human infections with variant influenza A H3N2 virus – also called “H3N2v” – have been detected in the United States since August 2011. You can track how many people get sick from this virus by visiting: Case Count: Detected U.S. Human Infections with H3N2v by State since August 2011.


Be Aware of How H3N2v Spreads.

Most of the infections with H3N2v have occurred after contact with pigs.  Influenza viruses are thought to spread from infected pigs to humans in the same way that seasonal influenza viruses spread between people:

  • Mainly, the spread of influenza happens when droplets infected with influenza spread through the air after an infected pig coughs or sneezes.  These droplets then land in your nose or mouth, or sometimes you inhale them.
  • There is also some evidence that you might be infected by touching something that has virus on it and then touching your own mouth or nose. 
  • A third way to possibly get infected is to inhale particles containing influenza virus.

Scientists are not really sure which of these ways of spread is the most common.

In some cases, the H3N2v virus seems to have spread from person-to-person.  So far, spread has not continued beyond one or two people.  The symptoms and severity of H3N2v illness have been similar to seasonal flu.


Take Action to Prevent Influenza Virus Spread Between People

You can reduce the risk of infection and spread of influenza viruses between people, including H3N2v, by taking a combination of actions. CDC recommends that you:

  • Take everyday preventive actions, including:

    • Try to avoid close contact with sick people.
    • Cover your nose and mouth with a tissue when you cough or sneeze. Be sure to throw the tissue in the trash after you use it.
    • Wash your hands often with soap and water, especially after you cough or sneeze.  If soap and water are not available, use an alcohol-based hand rub.
    • Avoid touching your eyes, nose, or mouth. Germs spread that way.
    • If you are sick, stay home from work or school until your illness is over.

The H3N2v virus is related to human flu viruses from the 1990s, so adults should have some immunity against these viruses, but young children probably do not.

Early steps to make a vaccine against H3N2v have been taken, but no decision to mass-produce such a vaccine has been made.  Seasonal vaccine is not designed to protect against H3N2v.  For more information, please visit Information on H3N2 Variant Influenza A Viruses.


Take Action to Prevent the Spread of Flu Viruses Between People and Pigs

You can reduce the risk of influenza viruses spreading from pigs to people by taking these actions.

  • Do not take food or drink into pig areas.
  • Do not eat, drink, or put anything in your mouth in pig areas.
  • Do not take toys, pacifiers, cups, baby bottles, strollers, or similar items into pig areas.
  • Wash your hands often with soap and running water before and after exposure to pigs.  If soap and water are not available, use an alcohol-based hand rub.
  • Avoid close contact with pigs if possible.
  • Take protective measures if you must be exposed to pigs that are known or suspected to be sick.  This includes:

    • limiting your contact with pigs
    • wearing personal protective equipment like:

      • protective clothing
      • gloves
      • masks that cover your mouth and nose when contact is required.
  • To further reduce the risk of infection, minimize contact with pigs and swine barns.
  • Watch your pig (if you have one) for signs of illness.

    • Call a veterinarian if you suspect it might be sick.
  • Avoid contact with pigs if you have flu-like symptoms.

    • Wait 7 days after your illness started or until you have been without fever for 24 hours without the use of fever-reducing medications, whichever is longer.
    • If you must have contact with pigs while you are sick, take the protective actions listed above.


Know if You Are at Higher Risk for Serious Flu Complications

Note that certain people are at “higher risk” for serious flu complications if they get infected with influenza viruses, including H3N2v. This includes:

  • children younger than 5 years
  • people 65 years and older
  • pregnant women
  • people with certain long-term health conditions like:

    • asthma and other lung disease
    • diabetes
    • heart disease
    • weakened immune systems
    • neurological or neurodevelopmental conditions.

CDC has issued guidance for “high risk” people attending fairs where swine might be present.  If you are one of these individuals, avoid pigs and swine barns at fairs this year.


Know What to Do If You Get Sick.

At this time, CDC recommends the following:

  • If you go to a doctor for flu symptoms after being in direct or close contact with swine, tell your doctor about your exposure.
  • Flu signs and symptoms usually include:

    • fever
    • cough
    • runny nose
    • other possible symptoms, such as:

      • body aches
      • nausea
      • vomiting
      • diarrhea.
  • If you have flu symptoms, follow CDC’s regular recommendations for seeking treatment for influenza: 

a. Contact your doctor if you have symptoms of flu and are very sick or worried about your illness.

b. Contact your doctor as soon as possible if you have flu symptoms and are at greater risk of serious flu-related complications.  These individuals include:

  • young children
  • elderly persons
  • pregnant women
  • people with certain long-term medical conditions.

You can find a full list of people at higher risk of flu related complications at People at High Risk of Developing Flu-Related Complications.

The majority of recent H3N2v cases have been in children.

c. Your doctor may prescribe antiviral drugs that can treat the flu, including H3N2v.  These drugs work better for treatment the sooner they are started.  If your doctor prescribes antiviral drugs for you, you should finish all of the medication, according to your doctor’s instructions.

  • Also, whenever you have flu symptoms and are seeing a doctor, always remember to tell them if you:

    • have asthma
    • have diabetes
    • have heart disease
    • have neurological and neurodevelopmental conditions
    • are pregnant
    • are older than 65 or younger than 5 years.

These conditions and age factors put you at high risk of serious complications if you have the flu.

  • Your doctor will decide whether you need influenza testing and possible treatment.
  • There are influenza antiviral drugs that can be used to treat infection with H3N2v viruses as well as seasonal influenza viruses.  More information about influenza antiviral drugs is available at Treatment (Antiviral Drugs).


Do Not Worry About Eating Pork.

Swine influenza has not been shown to be transmissible to people through eating properly handled and prepared pork (pig meat) or other products derived from pigs.  For more information about how to properly handle and prepare pork, visit the USDA website fact sheet Fresh Pork from Farm to Table.


Know Where to Find the Most Current Information about H3N2v.

For up-to-date information about H3N2v, please visit the following sites from the Centers for Disease Control (CDC):

This article was adapted from the CDC Fact Sheet: Protect Yourself Against H3N2v.


For more information:

Go to the Pandemic Flu health topic.