Influenza is estimated to cause three to five million cases and 250,000 to 500,000 deaths worldwide each year. The most severe influenza pandemic, in 1918, infected up to 50 percent of the world’s population and caused 20 to 50 million deaths worldwide. The use of antiviral drugs can lessen the severity of disease. Vaccines against seasonal influenza are made yearly to defend against currently circulating strains; however, vaccines that can be produced quickly, affordably, and in mass quantity to respond to a potential influenza pandemic in real-time are not yet available.

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Key resources

Estimating Age-Specific Cumulative Incidence for the 2009 Influenza Pandemic: A Meta-analysis of A(H1N1)pdm09 Serological Studies From 19 Countries (2013)
An article that details the results of a meta-analysis conducted to provide insights into the global impact of the 2009 influenza A(H1N1) pandemic.
A website that provides fact sheets, reports, articles, videos, and other resources about influenza symptoms, treatment, prevention, and vaccination.

Featured PATH resources

Investigating Live Attenuated Influenza Vaccine Efficacy in Senegal (2013)
A fact sheet that describes a Phase 3 clinical study that PATH and its partners are conducting in Senegal to evaluate the clinical efficacy of an influenza vaccine.

More About Influenza (2012)
A web page that provides general information about influenza and the current vaccine landscape.

Page last updated: October 2013.