Demographic characteristics of 1520 UK patients hospitalised with pandemic H1N1 infection during the 2009/10 pandemic (The FLU-CIN Cohort) compared with source population and pre-pandemic hospital data on acute respiratory infection admissions.

Data are numbers (%), unless otherwise indicated.
†Census 2001 Data for comparison of sex (KS01 tables) were obtained from the Office for National Statistics (ONS) (www.statistics.gov.uk). ‡Demographic data on age distribution based on 2009 mid-year population estimates, ONS.
‡‡Ethnicity data from ONS (Census 2001 data, 2001 data from the General Register Office for Scotland and Northern Ireland Statistics and Research Agency). *Hospital Episodes Statistics (HES) data: primary discharge codes relating to possible influenza admissions (J06, J10, J11, J13–22) were considered for the pre-pandemic influenza active period Nov 2008-Mar 2009.