Excess Risk of Invasive Pneumococcal Disease (IPD) Persists in Adults with Comorbid Conditions in the Era of PCV13 Childhood and Adult Immunization

Abstract

BackgroundAdults with comorbid illness are known to be at excess risk of IPD. We evaluated the burden of IPD in adults, with and without comorbidity, during the period before and after introduction of PCV13 in children and selected adults.MethodsWe employed a retrospective cohort design and data from a large US healthcare claims repository. The study population included all adults aged ≥18 years who had ≥1 day of health benefits at any time from 2007–2015, and who met minimum criteria for characterizing comorbidity profiles. Study subjects were stratified by age (18–49, 50–64, and ≥65 years) and risk profile (“at-risk”, “high-risk”, and “healthy”) based on ACIP-identified indications for pneumococcal vaccination. Episodes of IPD were identified in each year of the study period, and rate ratios comparing IPD incidence in persons with at-risk and high-risk conditions, respectively, vs. healthy persons, were computed.ResultsA substantial decline in IPD was observed in 2013–2015 compared with 2007–2010 in healthy, at-risk, and high-risk adults in all age groups. However, the proportional decline was lower in those with high- risk and at-risk conditions, resulting in an increased rate ratio for adults with comorbid conditions (Table).TableIPD rates and rate ratios by age group and risk profileRisk ProfileAge Group (Yr)Annual Rate per 100K, by Time PeriodDecline in Annual Rate from 2007–2010 to 2013– 2015Rate Ratio (95% CI), by Time Period 2007–2010 2013–2015 2007–2010 2013–2015 Healthy 18–49 1.6 0.9 41% -- -- 50–64 3.8 2.6 31% -- -- ≥65 7.0 5.3 25% -- -- At-Risk 18–49 4.5 3.1 31% 2.8 (2.3, 3.6) 3.4 (2.5, 4.4) 50–64 9.9 8.2 17% 2.6 (2.3, 3.0) 3.1 (2.7, 3.7) ≥65 21.4 18.0 16% 3.1 (2.6, 3.5) 3.4 (2.8, 4.2) High- Risk 18–49 16.2 14.2 12% 10.1 (7.9, 12.9) 14.2 (10.9, 18.6) 50–64 27.6 23.5 15% 7.3 (6.3, 8.4) 9.0 (7.6, 10.6) ≥65 36.7 36.4 1% 5.2 (4.5, 6.1) 6.9 (5.7, 8.4) ConclusionIPD burden declined from the pre-PCV13 era. This decline was greatest in healthy adults (vs.. those with at-risk or high-risk conditions); adults with comorbid conditions, especially those ≥65 years old, appear to have benefited least from the direct and indirect impacts of PCV13 immunization. Greater understanding as to which serotypes cause disease in adults with comorbid conditions and which host factors in individuals predispose to IPD is needed to develop additional prevention strategies for high-risk groups.Disclosures S. I. Pelton, Pfizer: Board Member and Grant Investigator, Consulting fee, Research grant and Speaker honorarium; Merck vaccines: Board Member, Consulting fee and Speaker honorarium; GSK: Board Member, Consulting fee and Speaker honorarium; Sequiris: Board Member, Consulting fee and Speaker honorarium; R. Bornheimer, Pfizer, Inc: Consultant, Consulting fee; K. M. Shea, Pfizer, Inc: Consultant and Grant Investigator, Consulting fee and Grant recipient; R. Sato, Pfizer, Inc: Employee and Shareholder, Salary; D. Weycker, Pfizer, Inc: Consultant, Consulting fee