Increase in tympanostomy tube placements despite pneumococcal vaccination, a population-based study

Abstract

Aim: The aim was to estimate the impact of the 10-valent pneumococcal vaccine (PHiD-CV) on tympanostomy tube placements (TTP) in children under five years of age in Iceland.

Methods: This population-based observational cohort study followed 11 consecutive birth-cohorts 2005-2015 from birth until their fifth birthday. Population registries were merged using national identification numbers. The risk of TTP was compared between birth-cohorts adjusted for the number of previous otitis media diagnoses and antimicrobial prescriptions. A Cox regression model was applied and the hazard ratio (HR) of TTP was estimated between each birth-cohort and the last vaccine non-eligible birth-cohort. The vaccine impact of PHiD-CV10 on TTP was estimated as 1-HR ×100%.

Results: In total, 51 247 children were followed for 210 724 person-years, of which 14 351 underwent 20 373 procedures. The estimated vaccine impact on TTP was -6% (95% CI -16% to 2.7%). Children in the vaccine-eligible cohorts had fewer previous otitis media diagnoses and had been prescribed fewer antimicrobials prior to the procedure than children in the vaccine non-eligible cohorts.

Conclusion: Despite high uptake of PHiD-CV10, tympanostomy procedures increased in Iceland during the study period. Vaccine-eligible children had milder disease prior to the procedure. The reason underlying these findings are speculative.

Keywords: Streptococcus pneumoniae; Conjugate vaccines; Middle ear ventilation; Otitis media; PHiD-CV vaccine.

Figure 1

The incidence rate of tympanostomy tube procedures per 100 person‐years for each birth‐cohort is depicted, stratified by six‐month age groups. Estimates are illustrated as points with error‐bars indicating 95% confidence intervals. Vaccine non‐eligible cohorts (VNEC) are illustrated in light grey and vaccine‐eligible cohorts (VEC) in dark grey. The incidence rate ratios between VEC and VNEC are written in along with 95% confidence intervals.

Figure 2

The hazard ratio (HR) of tympanostomy tube placement between each birth‐cohort and the last vaccine non‐eligible birth‐cohort are depicted, as estimated by three Cox regression models. At the top, unadjusted HR estimates are illustrated. HR estimates adjusted for the number of prior otitis media visits compromises the middle and prior antimicrobial prescriptions are illustrated at the bottom.