Effect of the 13-Valent Pneumococcal Conjugate Vaccine on Pneumococcal Meningitis in Children

To the Editor—We read with interest the recent article of Olarte et al [1] about the impact of the 13-valent pneumococcal conjugate vaccine (PCV13) on pneumococcal meningitis (PM) in US children. As have others, the authors observed an important decrease in invasive pneumococcal disease (IPD) after PCV13 implementation (from 229 cases in 2009 to 127 in 2013) [1–3]. Compared with the pre-PCV13 period, the proportion of PM cases modestly decreased after PCV13 implementation among children <24 months old, but the proportion of PM cases among IPD episodes increased 50%. We believe that several issues should be discussed. First, Olarte et al [1] did not find a significant reduction in PM in children <2 years old. By contrast, we have observed different results in France. Using our large cohort of pediatric patients with bacterial meningitis (227 pediatric wards) and adding findings from 2013 (1752 total cases of bacterial meningitis from 2009 to 2013), we observed a greater impact of PCV13 among children <2 years old than we previously reported [4]. Indeed, after PCV13 implementation, from 2009 to 2013, the number of PM cases among these children decreased by 38.8% (from 85 to 52; P = .002, Cuzick trend test), whereas for older children, the number of PM cases remained stable and did not increase.