Influenza A (H3N2) Variant Virus Outbreaks

Since July 2012, there have been outbreaks of H3N2 variant viruses with the matrix (M) gene from the 2009 H1N1 pandemic virus in multiple U.S. states. Investigations into H3N2v cases indicate that the main risk factor for infection is prolonged exposure to pigs, mostly in fair settings. Found in U.S. pigs in 2010 and humans in July 2011, this virus appears to spread more easily from pigs to people than other variant viruses. Though limited person-to-person spread with this virus has occurred, no sustained community spread of H3N2v has been detected at this time. Associated illness so far has been mostly mild with symptoms similar to seasonal flu and most cases have occurred in children who have little immunity against this virus. Like seasonal flu, however, serious illness, resulting in hospitalization and death is possible. People at high risk of serious complications from H3N2v include children younger than 5, people with certain chronic conditions like asthma, diabetes, heart disease, weakened immune systems, pregnant women and people 65 years and older. These people are urged to avoid pigs and pig arenas at fairs this season. The Centers for Disease Control and Prevention (CDC) is working with states to respond to these outbreaks and continues to monitor the situation closely.
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Background

CDC Assessment

Preventive Actions

CDC Recommendations For People At High Risk:

If you are at high risk of serious flu complications and are going to a fair where pigs will be present, avoid pigs and swine barns at the fair this year. This includes children younger than 5 years, people 65 years and older, pregnant women, and people with certain long-term health conditions (like asthma, diabetes, heart disease, weakened immune systems, and neurological or neurodevelopmental conditions).

If you are not at high risk, take these precautions:

Don’t take food or drink into pig areas; don’t eat, drink or put anything in your mouth in pig areas.
Don’t 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 that look or act ill.
Take protective measures if you must come in contact with pigs that are known or suspected to be sick. This includes minimizing contact with pigs and wearing personal protective equipment like protective clothing, gloves and 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.