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About: H1N1 Flu

Update

On August 10, 2010, the World Health Organization (WHO) declared an end to the 2009 H1N1 influenza pandemic. This declaration was based on strong indications that influenza (the flu), worldwide, is moving toward seasonal patterns of spreading.

This does not mean that the H1N1 virus has disappeared. Rather, it means current flu outbreaks, including those primarily caused by the 2009 H1N1 virus, show an intensity similar to that seen during seasonal epidemics. Pandemics, like the viruses that cause them, are unpredictable. WHO noted that continued vigilance is extremely important. It is likely that the virus will continue to cause serious disease in younger age groups and pregnant women, at least in the immediate post-pandemic period.

More information is available on the WHO website. ()

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What is H1N1?

H1N1 (sometimes called “swine flu”) is a new influenza virus causing illness in people. It’s thought that H1N1 spreads in the same way that regular seasonal influenza viruses spread; mainly through the coughs and sneezes of people who are sick with the virus.

This virus was originally referred to as “swine flu” because laboratory testing showed that many of the genes in this new virus were very similar to influenza viruses that normally occur in pigs (swine) in North America. But further study has shown that this new virus is very different from what normally circulates in North American pigs.

At this time, most people who have become ill with 2009 H1N1 in the United States have recovered without requiring medical treatment and have experienced typical flu symptoms.

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Symptoms

The symptoms of H1N1 flu virus in people include:

• Fever
• Cough
• Sore throat
• Runny or stuffy nose
• Body aches
• Headache
• Chills
• Fatigue
• Some people may have vomiting and diarrhea
• People may be infected with the flu, including 2009 H1N1 and have respiratory symptoms without a fever. Severe illnesses and deaths have occurred as a result of illness associated with this virus.

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History

H1N1 was first detected in Mexico and the United States in March and April, 2009. The first H1N1 patient in the United States was confirmed by laboratory testing at CDC on April 15, 2009. The second patient was confirmed on April 17, 2009. It was quickly determined that the virus was spreading from person-to-person. On April 22, CDC activated its Emergency Operations Center to better coordinate the public health response. On April 26, 2009, the United States Government declared a public health emergency.

Since the outbreak began in the United States, an increasing number of U.S. states have reported cases of 2009 H1N1 influenza with associated hospitalizations and deaths. By June 3, 2009, all 50 states in the United States and the District of Columbia and Puerto Rico reported cases of 2009 H1N1 infection. Nationwide () as well as Columbus and Franklin County () influenza surveillance reports indicate overall influenza activity is decreasing in the country at this time.

On August 10, 2010, the World Health Organization (WHO) declared an end to the 2009 H1N1 influenza pandemic. This declaration was based on strong indications that influenza (the flu), worldwide, is moving toward seasonal patterns of spreading.

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Vaccine Info

The U.S. 2010-2011 influenza vaccine will protect against the 2009 H1N1 influenza virus. Learn more about Prevention and Treatment.

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