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

Abstract 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)