1397. Long term impact of the 13-valent pneumococcal conjugate vaccine use in infant immunization program on all-cause pneumonia hospitalizations in British Columbia, Canada: a time series analysis

BACKGROUND: Pneumonia is a leading cause of hospitalization and in-patient mortality globally. We determined the impact of 13-valent pneumococcal conjugate vaccine (PCV13) use on all-cause pneumonia hospitalization rates eight years after the vaccine was introduced in British Columbia, Canada. METHODS: Routine administrative databases, such as, hospital discharge abstract databases, registry and demographics were used to build the cohort. Overall and age-specific all-cause pneumonia hospital admissions per month (Jan 2000 to Dec 2018) for those aged < 2 years, 2-5 years, 6-17 years, 18-64 years and ≥ 65 years were obtained using International Classification of Diseases 9 and 10 codes (480-486, J12-J18). Changes in the all-cause pneumonia hospitalization incidence rates before and after the PCV13 vaccine program introduction were evaluated using a negative binomial regression and time-series modelling while adjusting for seasonality, influenza-likeness illnesses, 7-valent pneumococcal conjugate vaccine (PCV7) program and pre-PCV13 vaccine secular trends. RESULTS: Long term use of the PCV13 vaccine in the infant immunization program was associated with significant declines in all-cause pneumonia hospitalization rates among all children, < 2 years (IRR: 0.63; 95% Confidence Interval (CI): 0.59-0.67), 2-5 years (IRR: 0.82; 95%CI: 0.77-0.87) and 6-17 years (IRR: 0.73; 95%CI: 0.69-0.78). All-cause pneumonia rates did not change significantly in those aged 18-64 years (IRR: 0.98; 95%CI: 0.96-1), whereas a modest increase was observed in those 65 years and over (IRR: 1.05; 95%CI: 1.02-1.07). Consequently, we did not observe significant change in the overall rate (IRR: 1.02; 95%CI: 1-1.02). CONCLUSION: Significant reduction in all-cause pneumonia hospitalization rates in children demonstrates long term beneficial effect of PCV13 use. A modest increase in all-cause pneumonia hospitalization rates in adults aged 65 years and over indicates a need for further microbial investigation. DISCLOSURES: Nirma Khatri Vadlamudi, BA, BS, MPH, Pfizer Inc (Research Grant or Support) Fawziah Marra, BSc (Pharm), PharmD, Pfizer Inc (Research Grant or Support)