Incidence of hospitalized all-cause pneumonia, and serotype distribution of hospitalized streptococcus pneumoniae pneumonia in Norway 2008-2009

Introduction: Pneumonia and Streptococcus pneumoniae pneumonia cause substantial disease in all ages. Objectives : Estimate incidence of all cause (PN) and pneumococcal pneumonia (PP) among all ages in Norway, 2008-2009. Methods: Retrospective database analysis was performed. Hospitalized patients with pre-identified International Classification of Disease 10 codes (ICD10) were identified from the Norwegian Patient Registry (NPR). Serotype information was available for a subset of patients with laboratory-confirmed invasive PN from reportable pathogens collected by the Norwegian Surveillance System for Communicable Diseases (MSIS). Population data were obtained from Statistics Norway (2008: 4,737,171; 2009: 4,799,252). Results: In 2008 and 2009 respectively 22,640 and 23,527 patients were hospitalized for pneumonia (all ages) with incidence rates of 5.28/1000 and 5.35/1000 persons/year. Rates in 2009 were highest in children 0-4 years (6.78/1000) and adults ≥65 years (21.4/1000). Incidence of hospitalization due to PP decreased from 13.66/100,000 to 10.52/100,000 from 2008 to 2009. In 2009 hospitalized PP incidence was highest in adults ≥65 years 35.61/100,000 and children 0-4 years 11.39/100,000. For PP patients with invasive isolates sent to MSIS (2008: 405; 2009: 302), serotypes in 7-valent pneumococcal conjugate vaccine (PCV7) decreased from 34.9% to 19.8%, while for 13-valent it remained high (71.9% and 63.7%) respectively. Conclusions: After implementation of a pediatric PCV7 national immunization program in 2006 PP decreased however there remains a substantial burden of hospitalized PN and PP notably in adults ≥ 65 years.