An International Observational Study to Characterize Adults Who Are Hospitalized With Influenza or Other Targeted Respiratory Viruses

Following the sudden and unexpected emergence of influenza A(H1N1)pdm09 (2009 H1N1) virus, this observational study was initiated to estimate rates of morbidity and mortality and to examine predictors of severity among participants with 2009 H1N1 infection. In 2011, as surveillance indicated that 2009 H1N1 virus was co-circulating with other seasonal influenza A and B viruses worldwide, the protocol was expanded to include other influenza A subtypes and influenza B viruses. The current version of the protocol (released in August 2013) further broadens the scope of this observational study. With the recognition that novel respiratory viruses other than novel influenza A viruses, e.g., Middle East Respiratory Syndrome Coronavirus (MERS-CoV), could become prevalent and of major public health importance, the objectives of this protocol have been expanded.