Changes in invasive pneumococcal disease caused by streptococcus pneumoniae serotype 1 following introduction of pcv10 and pcv13: Findings from the pserenade project

Streptococcus pneumoniae serotype 1 (ST1) was an important cause of invasive pneumococ-cal disease (IPD) globally before the introduction of pneumococcal conjugate vaccines (PCVs) con-taining ST1 antigen. The Pneumococcal Serotype Replacement and Distribution Estimation (PSERE‐ NADE) project gathered ST1 IPD surveillance data from sites globally and aimed to estimate PCV10/13 impact on ST1 IPD incidence. We estimated ST1 IPD incidence rate ratios (IRRs) compar-ing the pre‐PCV10/13 period to each post‐PCV10/13 year by site using a Bayesian multi‐level, mixed-effects Poisson regression and all‐site IRRs using a linear mixed‐effects regression (N = 45 sites). Following PCV10/13 introduction, the incidence rate (IR) of ST1 IPD declined among all ages. After six years of PCV10/13 use, the all‐site IRR was 0.05 (95% credibility interval 0.04–0.06) for all ages, 0.05 (0.04–0.05) for <5 years of age, 0.08 (0.06–0.09) for 5–17 years, 0.06 (0.05–0.08) for 18–49 years, 0.06 (0.05–0.07) for 50–64 years, and 0.05 (0.04–0.06) for ≥65 years. PCV10/13 use in infant immunization programs was followed by a 95% reduction in ST1 IPD in all ages after approximately 6 years. Limited data availability from the highest ST1 disease burden countries using a 3+0 schedule constrains generalizability and data from these settings are needed.