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    James M. Steckelberg, M.D.

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Question

What's the difference between H1N1 flu and influenza A?

What's the difference between H1N1 flu and influenza A?

Answer

from James M. Steckelberg, M.D.

Flu (influenza) viruses are divided into three broad categories: influenza A, B or C. Influenza A is the most common type. H1N1 flu is a variety of influenza A. H1N1 indicates the viral serotype; it's a kind of shorthand for characteristics that identify the virus to your immune system and allow the virus to enter your cells.

There are many different strains of H1N1 flu. Varieties of influenza A (H1N1), influenza A (H3N2) and influenza B are included in each year's flu vaccine. This year, the vaccine protects against the strain of H1N1 flu that caused the 2009 pandemic.

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References
  1. Seasonal influenza: Types of influenza viruses. Centers for Disease Control and Prevention. http://www.cdc.gov/flu/about/viruses/types.htm. Accessed Nov. 12, 2010.
  2. Centers for Disease Control and Prevention, et al. Prevention and control of influenza with vaccines: Recommendations of the Advisory Committee on Immunization Practices (ACIP), 2010. MMWR. 2010;59:1. http://www.cdc.gov/mmwr/pdf/rr/rr59e0729.pdf. Accessed Aug. 2, 2010.
AN02041 Dec. 8, 2010

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