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. Disclosures All authors: No reported disclosures.