Cystic fibrosis and COPD have been identified as risk factors for severe illness with 2009 H1N1 [3] and the [27] , Chicago, IL, USA [28] , California, USA [43] , New York, USA [49] , Australia and New Zealand [37] , Canada [5] and Brazil [14] . Estimates of the general population and pregnant woman are based on data from the US Census Bureau or the World Health Organization.