Author Affiliations: National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia (Dr Fiore); and PATH, Seattle, Washington (Dr Neuzil).
The 2009 influenza A(H1N1) virus was first identified 8 months ago,1 but the virus has already had a substantial effect on human health. Influenza activity in the United States has remained higher than normal since May, and measures of severe illness such as hospitalizations and deaths during the summer and fall have been equal to or higher than rates usually observed in a typical winter influenza season in all age groups except older adults.2 Even though influenza activity has decreased in recent weeks in some states, there remains the possibility of continued activity through the traditional winter influenza season and the prospect of normal winter circulation of seasonal influenza viruses.
Fiore AE, Neuzil KM. 2009 Influenza A(H1N1) Monovalent Vaccines for Children. JAMA. 2010;303(1):73-74. doi:10.1001/jama.2009.1929