Earlier forms of the H1N1 virus were found in pigs. Over time, the virus changed (mutated) and infected humans. H1N1 was a new virus in humans in 2009, and it spread quickly around the world. Most of the people who got the H1N1 flu were ages 5 - 24.
During the 2010-2011 flu season, H1N1 virus (swine flu) did not cause widespread infections as it had in 2009-2010. The 2010-2011 seasonal flu vaccine also protected against swine flu, and a separate vaccine was not needed. The same is true for the 2011-2012 seasonal flu vaccine
Any flu virus can spread from person to person when:
- Someone with the flu coughs or sneezes into air that others breathe in.
- Someone touches a doorknob, desk, computer, or counter with the H1N1 germs on it and then touches their mouth, eyes, or nose.
- Someone touches mucus while taking care of a child or adult who is ill with the H1N1 flu virus.
You cannot get H1N1 flu virus from eating pork or any other food, drinking water, swimming in pools, or using hot tubs or saunas.
See also: Influenza vaccine.