Ouldali N, et al. - Researchers investigated how implementation of pneumococcal conjugate vaccines (PCVs) influenced pneumococcal meningitis incidence in children in France over a 16-year period. A great reduction in the incidence of pneumococcal meningitis in children less than 15 years old was observed early after PCV13 implementation. However, the long-term PCV efficacy was compromised by a sharp rebound in incidence linked to the emergence of serotype 24F.

Methods

• This quasi-experimental, population-based interrupted time-series analysis with a nationwide prospective survey was carried out over a 16-year period in France, including children aged younger than 15 years from 227 pediatric wards from January 2001 to December 2016.
• By the time-series model (based on segmented regression with autoregressive error), the estimated incidence of pneumococcal meningitis per 100,000 children (of a population of 12.6 million children in 2017) before and after PCV7 and PCV13 implementation was the main outcome.

Results

• A total of 1,778 children with pneumococcal meningitis were enrolled.
• A significant reduction in monthly incidence of pneumococcal meningitis was noted as a consequence of PCV13 implementation; from 0.12 per 100,000 children before PCV13 to a nadir of 0.07 in December 2014 (−38%, 95% CI −56.1 to −20.4; p < 0.0001).
• They noted a sharp increase during 2015 and 2016, (+2.3% per month, incidence of 0.13 per 100?000 children at the end of the study period, p=0.0002), primarily associated with an increase of serotype 24F, which was frequently penicillin resistant.