we compared risk factors , clinical presentation , and progression of patients
that host factors are an important contributor to H7N9 severity .
To provide insights into the pathogenesis of H7N9 virus infection , we compared risk factors , clinical presentation , and progression of patients hospitalized with H7N9 , H5N1 , and 2009 pandemic H1N1 ( pH1N1 ) virus infections .
The identification of known risk factors for severe seasonal influenza and the more protracted clinical course compared with that of H5N1 suggests that host factors are an important contributor to H7N9 severity .