Effectiveness of thirteen-valent pneumococcal conjugate vaccine to prevent invasive pneumococcal disease in Canada: A Canadian Immunization Research Network (CIRN) study

Abstract

The effectiveness of the 13-valent pneumococcal conjugate vaccine (PCV13) to prevent vaccine-serotype (VT) invasive pneumococcal disease (IPD) in children aged 2–59 months was assessed using data from 4 geographically defined areas in Canada with IPD surveillance, including immunization status. VT IPD cases and IPD controls with non-PCV13 types or PCV13-related serotypes (NVT/NR) during the years 2010–2019 were eligible. Vaccine effectiveness (VE) was estimated by the indirect cohort method, using multivariate logistic regression models. In total, 367 VT IPD cases and 564 NVT/NR IPD controls were included. VE of ≥1 dose of PCV13 against VT IPD was 70% [95% confidence interval: 49%–83%], lower against serotype 19A IPD (VE = 58%; 95%CI, 14%–80%) and against serotype 3 IPD (VE = 46%; 95%CI, −36% to 79%), but higher against all other PCV13 serotypes (VE = 90%; 95%CI, 78%–96%). Waning of protection was seen against all VT IPD, particularly for serotype 3, with a VE of 89% [54%–97%] during the first 5 months after the third dose but no protection remaining after 18 months. As serotype 3 and serotype 19A are still frequent causes of IPD in children, more effective vaccines are needed.