Incidence and Case Fatality Rates of Novel 2009 Pandemic A/H1N1 Influenza in England

During April 2009, novel pandemic A/H1N1 influenza virus began causing illness in the U.K. In this study, investigators used data from a mandatory reporting system, primary care surveillance networks, and a national phone- and Internet-based pandemic influenza service to estimate H1N1 incidence and influenza-associated mortality in England.

Between June 1 and November 8, 2009, an estimated 540,000 cases of H1N1 influenza occurred, and 138 confirmed deaths from H1N1 influenza were reported, for a case fatality rate of 26 per 100,000. Incidence and case fatality rates, however, varied by age. Children (age range, 5 to 14 years) had the highest estimated incidence rate and the lowest case fatality rate (11 per 100,000), whereas elders (age, ≥65…