Economic burden of pertussis among adults 50 years and above: a retrospective observational study in England

Introduction: Pertussis is a highly contagious bacterial respiratory infection affecting all ages. It remains under-recognized in the older adult population despite frequent complications. Aims and objectives: Estimate healthcare resource utilization (HCRU) and direct medical costs (DMC) per pertussis case, among adults ≥50 years of age (YOA) in England. Methods: A retrospective observational study merged data from the Clinical Practice Research Datalink GOLD, Aurum, and linked Hospital Episode Statistics datasets. Adults ≥50 YOA with a pertussis diagnosis from 2009–2018 were propensity score-matched to those without pertussis. HCRU (primary and secondary care) and DMC were estimated for multiple time periods around diagnosis (index). Results: Baseline characteristics and DMC were generally balanced between cases (N=1480) and controls (N=1480). HCRU was significantly higher in the pertussis cohort across all primary care and most secondary care categories 1 month prior to 11 months post index date (p<0.001; Figure). HCRU was highest in the month prior to index across categories. Increases were already observed at 6 to 1 months before index. The pertussis cohort had significantly higher adjusted mean annualized cost per case (+26.7%; 95% CI 15.9-38.5; p<0.001). Conclusion: Pertussis in adults ≥50 YOA significantly increases HCRU and DMC starting before diagnosis, highlighting the need for prevention.