In 2009, talk and fear of seasonal flu were eclipsed in a big way by fear of H1N1, earlier known as "swine flu," which began reaching across the globe, eventually killing almost between 14,000 and 18,500 people. Described as a pandemic by the World Health Organization (WHO), H1N1 eventually seemed to fade away in early 2010. By August 2010, the WHO declared H1N1 swine flu was "post-pandemic," the last phase of any pandemic.
However, H1N1 flu is still making people sick, even killing some patients in random areas of the world, and experts expect it to do so for years to come. According to the WHO and various news reports, cases of H1N1 were reported as recently as December 2011 in the United States, Argentina, Australia, Brazil, Cambodia, Cameroon, Chile, Costa Rica, Czech Republic, Honduras, India, Iran, Jamaica, Kenya, Mexico and Vietnam.
H1N1 is the official description of one form of swine flu, so named because it made the leap from pigs to people. The WHO officially calls it "influenza A(H1N1)pdm09."
In late 2011, a new strain of swine flu, one that also jumped from pigs to humans, had been identified as H3N2, or "swine-origin triple reassortant influenza A." As of mid-December, ten people, nine of whom were children living in Iowa, Indiana, Maine and Pennsylvania, had been diagnosed with H3N2. All cases were mild and the patients recovered.
Prevention, diagnosis and treatment of swine flu are very similar to seasonal flu.
In 2010 and 2011, the vaccine used to prevent H1N1 swine flu was included in the seasonal flu shot in order to prevent its further spread. Since then, the numbers of new cases have been reduced to only a handful of patients each year.
Scientists plan to include protection against H3N2 swine flu in the 2012-2013 vaccine.
Learn more about the prevention, diagnosis and treatment of seasonal flu, including guidelines for calling your doctor should problems occur.
• Read about H3N2 swine flu in Modern Medicine