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What do I need to know about the new swine flu?
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The new H1N1 virus is a type of influenza virus that has been around since the early 20th century. It is similar to other seasonal influenza viruses, but it has a few unique characteristics. First, it is more easily transmitted from person-to-person than most seasonal influenza viruses. Second, it can cause more severe illnesses in some people. Third, it is not yet clear how long immunity lasts after infection.