Influenza A 2009 H1N1 virus-related symptoms range from mild to severe. Many infected individuals are able to recover without medical treatment. Occasionally, some individuals require hospitalization, and these patients receive supportive care and antiviral treatment. Serious infections from the 2009 H1N1 virus have resulted in some patient fatalities, usually due to secondary bacterial pneumonia or other respiratory complications.
It is important to note that approximately 70% of the individuals that require hospitalization due to H1N1 infection, have also had one or more previously recognized underlying medical condition that may compromise an effective immune response. These conditions include, but are not limited to:
