The Flu Virus
Influenza, commonly known as flu, is a viral infection.1 There are many strains, or types, of flu some of which can cause more serious health problems than others. These strains often change in their composition, which means that once you’ve had flu, you may not be protected against future attacks containing these different strains.
Two types of the flu virus can cause disease – influenza A and B.2 Currently, there are two influenza strains (H1N1 and H3N2) known to infect humans.1 The flu virus circulates worldwide and can spread easily from person to person.1
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1. WHO fact sheet No. 211. Influenza (Seasonal). April 2009. http://www.who.int/mediacentre/factsheets/fs211/en/index.html. Accessed 30/03/2011.
2. Oxford JS, Lambkin R. Drug Design Today 1998;3:448-456.