Impact of 13-Valent Pneumococcal Conjugate Vaccination in Invasive Pneumococcal Disease Incidence and Mortality

Background. The impact of the 13-valent pneumococcal conjugate vaccine (PCV13) at the population level is unclear. We explored PCV13's effect in reducing invasive pneumococcal disease (IPD)–related morbidity and mortality, and whether serotype-specific changes were attributable to vaccination or expected as a part of natural, cyclical variations. Methods. This was a Danish nationwide population-based cohort study based on the linkage of laboratory surveillance data and the Danish Civil Registration System. Changes in IPD incidence and mortality during baseline (2000–2007), 7-valent pneumococcal conjugate vaccine (PCV7) (2008–2010), and PCV13 (2011–2013) periods were estimated. Predicted incidences of serotypes were estimated controlling for cyclical trends from historical patterns observed during the past 20 years. Results. We observed a 21% reduction (95% confidence interval [CI], 17%–25%) in IPD incidence in the total population after PCV13's introduction, and a 71% reduction (95% CI, 62%–79%) in children aged