H3N2v is a variant of H3N2 influenza virus that infected 321 people in the United States in 2011 and 2012. When this virus occurs in pigs, it is called “swine influenza.” The virus does not usually infect people or spread among people. It is very different from human seasonal H3N2 viruses.
- 307 of the cases occurred from July-November 2012.
- Symptoms of H3N2v are similar to seasonal flu symptoms.
- There has been limited person-to-person transmission and one death.
Is H3N2v a threat?
Most cases of H3N2v virus infection in 2011 and 2012 resulted in symptoms similar to seasonal flu: fever, cough, runny nose, sore throat, and muscle aches. A few people were hospitalized and recovered. There was one death reported of an older adult with multiple underlying health conditions. This occurred in Ohio in August 2012. The individual reportedly had direct exposure to pigs in a fair setting.
Most cases occurred after direct or close contact to pigs and many of these exposures have been at county agricultural fairs. CDC continues to closely monitor human infections with H3N2v viruses.
What are the symptoms of H3N2v flu?
So far, symptoms and severity of H3N2v are similar to the seasonal flu symptoms.
How does H3N2v spread?
H3N2v can spread to humans from infected pigs. In some cases, H3N2v also has spread between people. This happens in the same way that seasonal flu viruses spread—through close contact with sick people who may spread their infections through coughs or sneezes. Since there has been limited virus transmission from person-to-person, it is considered less contagious among people than the seasonal flu.
How can I avoid H3N2v flu?
You should follow everyday steps to keep yourself healthy this flu season. In addition, avoid close contact with animals, especially with pigs, that look or act sick. If you must come in contact with sick animals, you should take appropriate precautions such as wearing gloves.
A precautionary vaccine against H3N2v is in development and will likely be ready for clinical trials in the coming months.
Does seasonal flu vaccine protect against H3N2v?
The 2012-2013 seasonal flu vaccine is not designed to protect against H3N2v.
Is there an H3N2v vaccine?
Not at this time, but research and development into an H3N2v virus has taken place. Clinical trials are planned for later this year. However, manufacturers are in a position to produce a vaccine that protects against this strain should sustained human-to-human transmission of H3N2v occur.
What should I do if I think I have H3N2v?
If you live in an area where H3N2v cases have been identified recently and develop flu symptoms, contact your health care provider (doctor, physician’s assistant, etc…). Tell them if you have had contact with pigs or with other sick people. Your health care provider will determine whether influenza testing and possibly treatment are needed. Influenza antiviral drugs can treat H3N2v infection, just as they can treat seasonal flu infection.