Pandemic (H1N1) 2009 and Seasonal Influenza A (H3N2) in Children’s Hospital, Australia

摘要

To the Editor: We read with interest the report by Carcione et al. of clinical features of pandemic in. uenza A (H1N1) 2009 and comparison of these with 2009 seasonal in. uenza infection in a population-based study from Western Australia (1). Here we share our experience of hospitalizations for in. uenza in a tertiary care children's hospital in Sydney, New South Wales, Australia, during the 3 peak in. uenza seasons of the last decade.During the 2009 Southern Hemisphere single in. uenza wave (June–September), we prospectively studied every child <15 years of age who was hospitalized with laboratory-confi rmed in. uenza (74% had proven pandemic [H1N1] 2009) in Children's Hospital at Westmead (CHW), Sydney, as part of a collaboration between the National Centre for Immunisation Research and Surveillance and the Australian Paediatric Surveillance Unit. The study was approved by the Human Research Ethics Committee at CHW and supported by the state (New South Wales) health department. Data from hospitalizations for seasonal in. uenza at CHW in 2003 and 2007 (previous peaks in the last decade) were analyzed by using our previous studies and medical records (2–4). To compare pneumonia rates, we used the same case defi nitions in 2007 and 2009 (radiologic changes consistent with pneumonia). Proportions were compared by using the χ2statistic