title: Pneumonia in Elderly Australians: Reduction in Presumptive Pneumococcal Hospitalizations but No Change in All-Cause Pneumonia Hospitalizations Following 7-Valent Pneumococcal Conjugate Vaccination.
abstract: BACKGROUND
  Studies evaluating long-term trends in hospitalizations coded as pneumonia following introduction of the 7-valent pneumococcal vaccine (PCV7) are sparse, especially in adults. We extended our previous analysis to 6.5 years after the "3 + 0" PCV7 schedule was introduced in Australia in 2005.
  
  
  METHODS
  We estimated vaccine impact on hospitalizations coded as pneumonia (pneumococcal/lobar, other specified, unspecified, and all-cause) using a multivariate negative binomial regression model of monthly hospitalization rates by age group for the pre-PCV7 (July 1998 to December 2004) and post-PCV7 (January 2005 to June 2011) periods, adjusting for vaccination coverage. Changes in pneumonia hospitalizations were measured as incidence rate ratios.
  
  
  RESULTS
  A total of 791 000 hospitalizations coded as pneumonia were identified; unspecified causes accounted for >85%. Reductions in pneumonia coded as pneumococcal/lobar were statistically significant in all age groups and greatest in children. Significant reductions in all-cause pneumonia were seen only in children aged <2 years (32%; 95% confidence interval [CI], 28%-37%) and 2-4 years (20%; 95% CI, 14%-27%), with no significant changes in other age groups, including adults aged 65-74 (4%; 95% CI, -3% to 10%), 75-84 (2%; 95% CI, -4% to 9%), and ≥85 years (3%; 95% CI, -3% to 10%).
  
  
  CONCLUSIONS
  We could not replicate reductions of 23% in all-cause pneumonia 7-9 years post-PCV7 introduction reported for adults aged ≥85 years in the United States. This could be attributable to vaccine program factors, differing proportions of pneumonia due to pneumococci, or data limitations. More data from countries with differing PCV schedules and from the PCV13 era are needed to inform vaccination strategies for elderly adults.
authors.affiliation: National Centre for Immunisation Research and Surveillance, The Children's Hospital at Westmead, Sydney Sydney Medical School, University of Sydney.
authors.forename: Robert I
authors.initials: RI
authors.lastname: Menzies
authors.affiliation: National Centre for Immunisation Research and Surveillance, The Children's Hospital at Westmead, Sydney National Centre for Epidemiology and Population Health, Australian National University, Canberra.
authors.forename: Andrew
authors.initials: A
authors.lastname: Jardine
authors.affiliation: National Centre for Immunisation Research and Surveillance, The Children's Hospital at Westmead, Sydney Sydney Medical School, University of Sydney.
authors.forename: Peter B
authors.initials: PB
authors.lastname: McIntyre
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001315:Australia / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D000069443:Heptavalent Pneumococcal Conjugate Vaccine / Q000008:administration & dosage*; D006760:Hospitalization; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000453:epidemiology*; D014611:Vaccination / Q000706:statistics & numerical data; D055815:Young Adult
chemical_list: D000069443:Heptavalent Pneumococcal Conjugate Vaccine
keywords: Streptococcus pneumoniae; heptavalent pneumococcal conjugate vaccine; immunization schedule; pneumonia