The H1N1 swine flu virus appeared in the U.S. in April 2009 and never went away. After sweeping the globe, U.S. H1N1 swine flu cases surged as schools opened in the fall. What is H1N1 swine flu? What can we do about it? WebMD answers your questions.
What is swine flu?
What are swine flu symptoms?
Who is at highest risk of H1N1 swine flu?
Help! I've been exposed to swine flu. What should I do?
If I think I have swine flu,...