Influenza A (H3N2) Variant Virus [H3N2v]: Information for the General Public

What is H3N2v?
Some influenza A viruses occur naturally in pigs and can cause illness in those animals—these viruses are called “swine flu viruses”. While swine flu viruses do not normally infect humans, occasional human infections have occurred. When swine flu viruses infect humans, the viruses are called “variant viruses”.

The influenza A (H3N2) variant virus, or H3N2v, was first identified in pigs in the United States in 2010. In 2011, twelve cases of human infection with H3N2v occurred in five different states (not including Virginia). Since then, additional cases occurred, including one in 2013 in an out-of-state resident who had contact with swine in Virginia.

How can a person get H3N2v?
Influenza viruses can spread from people to pigs and from pigs to people. Spread from infected pigs to humans is thought to happen in the same way that seasonal influenza viruses spread between people – mainly through infected droplets created when an infected pig coughs or sneezes. If the droplets land in your nose or mouth, or you inhale them, you can be infected. Some evidence indicates that you might get infected by touching something that has virus on it and then touching your own mouth or nose.

How is H3N2v spread?
Most of the cases of H3N2v, including the one case with exposure in Virginia, had prolonged contact with pigs at agricultural fairs. Limited spread from person-to-person has also taken place; however, ongoing (sustained) transmission has not occurred.

What are the symptoms of H3N2v infection?
The symptoms of H3N2v infection are similar to the symptoms of seasonal influenza and can include fever and respiratory symptoms, such as cough and runny nose, and possibly other symptoms, such as body aches, nausea, vomiting, or diarrhea.

Is there a vaccine for H3N2v infection?
Currently, there is no vaccine for H3N2v infection. Scientists have taken early steps to start developing a vaccine; but, according to CDC, no decision to mass produce a vaccine has been made. The seasonal flu vaccine will not protect against H3N2v. Seasonal flu vaccines protect against seasonal influenza viruses. CDC recommends that everyone 6 months and older get a seasonal flu vaccine each year.

What is the treatment for H3N2v?
The same influenza antiviral drugs used to treat seasonal flu are used to treat H3N2v infection. The currently recommended drugs (oseltamivir and zanamivir) are available by prescription from your doctor. Early treatment works better and may be especially important for people with a high-risk condition. If you are prescribed antiviral drugs by your doctor, you should finish all of the medication, according to your doctor’s instructions.

How can I reduce the likelihood of getting H3N2v infection?

  • Some people are at higher risk for serious illness if they develop influenza, and should consider avoiding exposure to pigs and swine barns this fair season, especially if sick pigs have been identified. People at increased risk include children younger than 5 years old, people 65 years and older, pregnant women, and people with certain chronic medical conditions (like asthma, diabetes, heart disease, weakened immune systems, and neurological or neurodevelopmental conditions).
  • Wash your hands with soap and running water before and after exposure to pigs. If soap and water are not available, use an alcohol-based hand rub.
  • Never eat, drink, or put things in your mouth in pig areas, and don’t take food or drink into pig areas. Avoid close contact with animals that look or act ill.
  • Never take toys, pacifiers, spill-proof cups, baby bottles, strollers, or similar items into pig areas.
  • Cover your mouth and nose with a tissue or your sleeve (not your hands) when coughing or sneezing, and wash your hands often.
  • Avoid contact with pigs if you are experiencing flu-like symptoms. Avoid contact for 7 days after symptoms begin or until you have been fever-free for 24 hours without the use of fever-reducing medications, whichever is longer.
  • If you must be near pigs that are known or suspected to be infected with influenza viruses, wear gloves and a mask to cover your mouth and nose.
  • If you develop a flu-like illness after exposure to pigs, see your doctor. Tell the doctor that you have had recent exposure to pigs.

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