Rebound in the incidence of pneumococcal meningitis in northern France: effect of serotype replacement

Aim: To determine whether the recent emergence of nonvaccine pneumococcal serotypes has affected the incidence of pneumococcal meningitis in children a few years after the introduction of the heptavalent pneumococcal conjugate vaccine. Methods: We conducted a multicentre retrospective cohort study from 2005 to 2008 in all hospitals with paediatric units in northern France. It included all patients < 18 years of age who were admitted for laboratory-confirmed pneumococcal meningitis during the study period. Data were collected from medical files and laboratory records at each hospital and compared with the regional hospital discharge codes. We assessed global and age-specific incidence rates of pneumococcal meningitis from 2005 through 2008, compared them with those from the prevaccine era (2000-2002) and evaluated pneumococcal serotypes. Results: In all, 41 cases were found during the study period. The incidence rate of pneumococcal meningitis varied from 0.8/100 000 children < 18 years in 2005 to 1.8/100 000 children in 2008 (2.2-fold increase, p = 0.06); and from 1.8 to 11.9/100 000 children < 2 years (6.5-fold increase, p = 0.004). This increase was caused by nonvaccine pneumococcal serotypes. Conclusion: The incidence of pneumococcal meningitis in infants has rebounded in northern France during the pneumococcal conjugate vaccine programme, with the emergence of nonvaccine pneumococcal serotypes.