2718. Effectiveness of 13-Valent Pneumococcal Conjugate Vaccine in US Adults Hospitalized with Pneumonia, 2014–2017

Abstract

Background: Efficacy of 13-valent pneumococcal conjugate vaccine (PCV13) against pneumococcal pneumonia in adults aged >65 years was shown in a 2014 clinical trial. However, its benefits in countries with a mature PCV infant program remain unclear. In August 2014, PCV13 was recommended for all US adults aged >65 years. We evaluated the direct effect of this recommendation on pneumonia hospitalizations among the elderly. Methods: We analyzed claims data from US Medicare beneficiaries aged >65 years enrolled in part A/B during September 1, 2014 through December 31, 2017. Participants were followed until they died, left part A/B, or developed a study outcome: community-acquired pneumonia (CAP), non-healthcare-associated CAP (non-HA CAP) or lobar pneumonia (LP). We identified outcomes using inpatient diagnosis codes, and vaccination status using procedure codes. We used discrete-time survival models, stratified by influenza season (October-April) and influenza vaccination status, to estimate incidence rate ratios (IRR) by pneumococcal vaccination status (PCV13-only vs. no pneumococcal vaccination). We adjusted for demographic factors, healthcare utilization, month/year of hospital discharge, and underlying conditions. We derived vaccine effectiveness (VE) and number of hospitalizations averted by PCV13 from the IRRs. Results: Of 26.6 million beneficiaries in September 2014, 43.4% were male, 54.2% were aged 65-74 years, and 28.9% had a Charlson comorbidity score >3. PCV13 coverage increased from 0.8% in September 2014 to 41.5% in December 2017. Annual incidence of CAP, non-HA CAP, and LP are shown in the figure. PCV13-vaccinated persons were more likely to be older, sicker, and have received flu vaccine than unvaccinated persons. VE estimates for CAP, non-HA CAP, and LP ranged from 6.0-11.4%, 5.0-11.0%, and 1.3-11.0%, respectively. From September 2014 to December 2017, an estimated 28,600 (95% CI: 21,000-36,000) CAP, 18,700 (12,000-25,800) non-HA CAP and 1,100 (190-1,900) LP hospitalizations were averted. Conclusion: Within 40 months after implementation of the adult PCV13 program, 2.0% (28,600) of US CAP hospitalizations were averted. Despite PCV13 effectiveness against adult CAP, only a small fraction of CAP hospitalizations was prevented. (Figure Presented).