2706. Indirect Effects of Infant 13-valent Conjugate Pneumococcal Vaccination Program on Invasive Pneumococcal Disease in Adults in British Columbia, Canada

BACKGROUND: Many jurisdictions report a significant reduction in invasive pneumococcal disease (IPD) in adults following implementation of the pneumococcal conjugate vaccines, 7-valent (PCV7) and 13-valent (PCV13) in childhood immunization programs. This study evaluates the indirect effect of conjugate vaccines on IPD in British Columbia, Canada over a 14 year period (2002–2015). METHODS: Using provincial IPD laboratory surveillance data, we calculated the annual incidence following implementation of PCV7 (September 2004), and PCV13 (September 2010) in adults 18 years of age and older. We also compared incidence rate ratios (IRR) against pre-PCV13 (2004–2010) and pre-PCV7 (2002–2003) baselines for overall and age-specific IPD rates using Poisson regression. RESULTS: A total of 3793 cases were reported over the 14 year period. The overall annual incidence increased from 4.32 cases per 100,000 population in 2002 to 8.61 cases per 100,000 population in 2015. Overall, IPD has increased by 80% (IRR: 1.80; 95% CI: 1.59–2.04) compared with baseline, especially in adults ≥ 85 years of age (PCV13 vs baseline: IRR: 1.90; 95% CI: 1.25–03.05). This increase was the highest after introduction of PCV7 (IRR: 1.87; 95% CI: 1.65–2.11); the incremental change after introduction of PCV13 was non-significant (IRR 0.96; 95% CI: 0.90–1.03). While PCV7 type IPD plummeted by 76% (IRR 0.24; 95% CI: 0.18–0.31) since introduction of PCV7 compared with baseline, a modest decline in PCV13 type IPD of 20% was seen (IRR 0.80; 95% CI: 0.71–0.89) since introduction of PCV13. CONCLUSION: Although PCV7-type IPD has decreased substantially, only a modest reduction in IPD from the additional 6 serotypes in the PCV13 vaccine was observed. DISCLOSURES: All authors: No reported disclosures.