Comparison of pandemic and seasonal influenza reveals higher mortality and increased prevalence of shock in children with severe h1n1/09 infection.

Comparison of the clinical features of H1N1/09 and previous years' influenza A cases reveals that, in children presenting with severe disease, H1N1/09 influenza is associated with an increased prevalence of shock, duration of admission, and mortality. This was not attributable to demographic differences or underlying disease. H1N1/09 influenza is associated with more severe diseases than those with previous years' influenza A strains.