Invasive pneumococcal disease and otitis media due to pneumococci disproportionately affect remote dwelling First Nations Australian children, driven by nasopharyngeal colonisation by respiratory pathogens in the first weeks of life. Microbiological samples have been collected from surveillance studies and clinical trials since 1996. We aimed to explore trends in nasopharyngeal (NP) pneumococcal carriage over time, and factors associated with serotype distribution and resistance.
This study collated NP microbiological data from the non-interventional arms of trials and cross-sectional studies. Carriage and serotype-specific rates by age category in the differing conjugate vaccine eras will be described. Hierarchical logistic regression will be used to account for confounders (age, clustering within individuals and communities).
Interim findings from over 9,000 NP swabs from children with a median age of 19 months (range 0-18 years) suggest expected reductions in vaccine type pneumococci, with no significant change in overall carriage rates, replacement by non-vaccine serotypes with persistent low-level carriage of vaccine types. 16F was the most commonly isolated serotype, with 50% non-susceptible to penicillin.
Understanding the impact of PCVs on serotype dynamics and antibiotic non-susceptibility of S.pneumoniae in this remote-dwelling population will strengthen evidence for vaccine policy and ongoing antimicrobial stewardship in the region.