1918–1919 | 2009 | |
---|---|---|
Influenza virus | Avian Influenza A H1N1 | Swine-Origin-Influenza A(H1N1)v |
Social and political Context | World War I – U.S. troops being deployed to Europe | One of the largest economic recessions in the U.S. with worldwide reach |
Globalization, ease of travel, population overgrowth, megacities | ||
Source of viral strain emergence | Historians have suggested to potential origins for this pandemic viral strain in China or in the Midwestern US military camps during World War I | Unclear source, phylogeny of the virus demonstrates to be an Eurasian H1N1 swine strain |
Seasonality and transmissibility | Highly-transmissible – three succeeding waves of the outbreak | Cases surfaced in early spring in Mexico City and in California, U.S.A. |
Initial wave spring 1918 with sustained multifocal transmission | Sustained transmission (two generations) only in North America | |
Affected age groups | Most deaths occurred within the first six months of the pandemic. | Most deaths occurred within a three week time span. |
Most affected group 15–34 year-old population | Most affected group is the 5 to 30; case-fatality rate has ranged from 5 to 45 years of age | |
Case management | Insufficiency of healthcare systems | Wider availability of healthcare institutions |
Absence of effective antimicrobials for treating secondary bacterial pneumonias. | Availability of broad-spectrum antimicrobials for treating secondary bacterial pneumonias | |
Medical intensive care in early phases of development | Sophisticated medical intensive care and mechanical ventilatory support | |
Insufficient infection control activities | More established infection control activities and programs | |
Virulence | Highly virulent | Virulence only demonstrated as causing most fatalities in Mexico |
Availability of vaccine | No | No |
Susceptibility to antivirals | No availability of antivirals | Susceptibility to neuraminidase inhibitors (oseltamivir). However, there are growing number of resistant viral strains to oseltamivir |
Nosocomial transmission | Highly transmissible in hospital settings | Possibility of nosocomial transmission under investigation with 81 healthcare workers affected in the U.S [23] |
Molecular characterization | H1N1 avian strain without evidence of reassortment (4) | H1N1 (triple reassortant – human – avian – swine) |
Natural history of the outbreak and outcomes | More than 300 million cases worldwide | By June 11, 2009, 74 nation states have cases, with approximately 27,737 confirmed cases and 141 death |
More than 50 million people deaths worldwide |