Risk factors and outcomes for pandemic H1N1 influenza compared with seasonal influenza in hospitalized children in China

OBJECTIVE: To compare clinical features and outcomes of children hospitalized in China with pandemic (p)H1N1 between 2009 and 2010 versus seasonal influenza A between 2008 and 2009. METHODS: Systematic review of laboratory-confirmed admissions to the Children's Hospital, Soochow University (Suzhou, China). RESULTS: Seventy-five children younger than 14 years of age were admitted with pH1N1, 70 with H3N2 and three with seasonal H1N1. With pH1N1, the mean age was older (36 months versus seven months), the length of stay was longer (nine days versus seven days), underlying conditions were more common (29% versus 15%), anemia was more common (11% versus 0%) (P<0.05), with trends toward more secondary bacterial pneumonia and intensive care unit care, compared with seasonal influenza. Tw o of the 75 children with pH1N1 died versus no deaths in children with seasonal influenza. None of the children had received pH1N1, seasonal influenza, conjugated pneu-mococal or Haemophilus influenzae b vaccines. CONCLUSION: In China, children hospitalized with pH1N1 influenza differed from case series in Canada, Argentina and the United States, suggesting that locale, background and health care system influenced the presentation and outcomes of pandemic and seasonal influenza.