Keywords:
All-cause pneumonia, Children, Hospitalizations, Pneumococcal vaccines, Respiratory pathogens
Abstract:
Background. Pneumococcal conjugate vaccine (PCV) was included in Australia s National Immunisation Program for all children from 2005. We assessed the impact of PCV on all-cause and pathogen-specific pneumonia hospitalizations in Western Australian (WA) children aged ?16 years. Methods. All hospitalizations with pneumonia-related International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Australian Modification diagnosis codes occurring in WA-born children (1996 2012) were linked to pathology records. Age-specific incidence rate ratios and temporal trends for all-cause and pathogen-specific pneumonia hospitalizations were calculated before and after PCV introduction. Results. Among 469 589 births, there were 15 175 pneumonia-related hospitalizations. Hospitalization rates were 6.7 (95% confidence interval, 6.4 6.9) times higher in Aboriginal than in non-Aboriginal children. Following PCV introduction, all-cause pneumonia hospitalizations showed significant declines across all age groups. A pathogen was identified in 2785 of 6693 (41.6%) pneumonia hospitalizations that linked to a pathology record. Respiratory syncytial virus (RSV) was most frequently identified, with RSV-associated pneumonia hospitalization rates of 89.6/100 000 child-years in Aboriginal and 26.6/100 000 child-years in non-Aboriginal children. The most common bacterial pathogen was Streptococcus pneumoniae in Aboriginal children (32.9/100 000 childyears) and Mycoplasma pneumoniae in non-Aboriginal children (8.4/100 000 child-years). Viral pneumonia rates declined in all children following PCV introduction, with the greatest declines seen in non-Aboriginal children; declines in bacterial pneumonia were observed in non-Aboriginal children. Conclusions. Based on our ecological analyses, PCV seems to have had an impact on hospitalizations for pneumonia, suggesting that the pneumococcus is likely to play a role in both bacterial and viral pneumonia. Respiratory viruses remain an important pathogen in childhood pneumonia. Vaccines targeting respiratory viruses are needed to combat the residual burden of childhood pneumonia.