Ricketson, LeahKellner, James DCASPER Investigators2022-06-132022-06-132022-06-20Ricketson, L., Kellner, J. D., & CASPER Investigators (2022, June 19-23). Pneumococcal Disease Trends in the Post-Vaccine Era in Calgary, Canada: An Interrupted Time Series Analysis [Poster presentation]. 12th International Symposium on Pneumococci and Pneumococcal Diseases, Toronto, Canada. https://isppd.kenes.com/http://hdl.handle.net/1880/11473712th International Symposium on Pneumococci and Pneumococcal Diseases (ISPPD-12), Toronto, Canada, June 19-23, 2022Background: In 2002 the 4-dose 7-valent pneumococcal conjugate vaccine (PCV7) was introduced in Calgary for vaccination of children, followed by the 3-dose 13-valent vaccine (PCV13) in 2010. Methods: We conducted an interrupted time series analysis on incidence of IPD per quarter allowing for change in trends in 2002 and 2010. We included models for IPD overall and age and serotype restricted models. Results: The incidence of PCV7 IPD (all ages) decreased after PCV7 introduction in 2002 (P<0.001) and was sustained after PCV13 introduction in 2010. In children, the incidence of PCV13 (less PCV7 ST) IPD increased in children after PCV7 introduction (P<0.001) and decreased after PCV13 introduction (P=0.002). After PCV7 introduction, overall IPD incidence was lower in children, but not significant, (P=0.054) and was unchanged in adults (P=0.4721). After PCV13 introduction, overall IPD incidence was unchanged in children (P=0.88) and increased in adults (P<0.001). Conclusions: PCV7 IPD has declined in the post-PCV period, but overall IPD had not declined significantly and was increasing in adults prior to the precipitous decline observed in 2021, during the COVID-19 pandemic. PCV13 serotypes, as well as non-vaccine serotypes, continue to cause disease, including outbreaks of serotype 4, 5, and 8. It is unclear whether the change from 4 doses to 3 doses of PCV has reduced overall vaccine effectiveness.engStreptococcus pneumoniaepneumococcusvaccinespneumococcal conjugate vaccinesinterrupted time series analysisconference poster10.11575/PRISM/39825