Mortality attributable to pandemic influenza A (H1N1) 2009 in San Luis Potosí, Mexico.

Background: Acute respiratory infections are a leading cause of morbidity and mortality worldwide. Starting in 2009, pandemic influenza A(H1N1) 2009 virus has become one of the leading respiratory pathogens worldwide. However, the overall impact of this virus as a cause of mortality has not been clearly defined.