Update on avian influenza : november 2006

Abstract

Data collected from human cases in Vietnam and Thailand since 2003 show that disease and mortality from H5N1 avian influenza tends to be more severe among children than adults. This is complicated by the fact that severe and fatal H5N1 infections in children and adolescents have been shown to occur in the absence of respiratory presentations or marked respiratory involvement. This represents an apparent change in the epidemiology of the H5N1 virus in humans subsequent to the 1997 outbreak in Hong Kong. where severe disease symptoms were seen less frequently among children than adults.