title: Influenza epidemiology--past, present, and future.
abstract: In April 2009, Mexican, American, and Canadian authorities announced that a novel influenza virus with pandemic potential had been identified in large segments of the population. Within weeks, it became apparent that the world was dealing with the first influenza pandemic in >40 yrs. Despite the unpredictable nature of influenza severity and spread in the pandemics of the 20th century, understanding the epidemiology of the past pandemics and current influenza pandemic will help prepare physicians, hospitals, and governments to predict and prepare for the subsequent waves and subsequent pandemics. We present a summary of the biology that predisposes influenza to cause sudden pandemics, as well as a summary of the epidemiology of the 20th century pandemics. We also report on the epidemiology, disease severity, and risk factors for severe disease and intensive care admission from the first wave of the current pandemic (April-August 2009). Last, we provide a mathematical model based on transmission dynamics of the H1N1 influenza virus that may provide some guidance in terms of disease incidence and hospital impact.
authors.affiliation: Department of Medical Microbiology and Infectious Diseases, Faculty of Medicine, University of Manitoba, Manitoba, Canada. plagacewiens@sbgh.mb.ca
authors.forename: Philippe R S
authors.initials: PR
authors.lastname: Lagacé-Wiens
authors.forename: Ethan
authors.initials: E
authors.lastname: Rubinstein
authors.forename: Abba
authors.initials: A
authors.lastname: Gumel
mesh_terms: D000956:Antigens, Viral / Q000276:immunology; D000998:Antiviral Agents / Q000627:therapeutic use; D004196:Disease Outbreaks / Q000266:history*; D024882:Drug Resistance, Viral; D049673:History, 20th Century; D006801:Humans; D015994:Incidence; D053118:Influenza A Virus, H1N1 Subtype; D053121:Influenza A Virus, H2N2 Subtype; D053122:Influenza A Virus, H3N2 Subtype; D007252:Influenza Vaccines; D007251:Influenza, Human / Q000453:epidemiology / Q000266:history* / Q000276:immunology; D008954:Models, Biological; D014944:World Health Organization
chemical_list: D000956:Antigens, Viral; D000998:Antiviral Agents; D007252:Influenza Vaccines