Impact of 13-valent pneumococcal conjugate vaccine on pneumococcal meningitis in children.

OBJECTIVES:To evaluate the impact of 13-valent pneumococcal conjugate vaccine on pneumococcal meningitis in children. METHODS:Children younger than 15years of age attending 27 hospitals in the Region of Madrid with confirmed pneumococcal meningitis were identified in a prospective surveillance study, from 2007 to 2015. Clinical data, neurological sequelae, pneumococcal vaccination status, serotyping and antibiotic susceptibility were recorded. RESULTS:One hundred and four cases of pneumococcal meningitis were identified, 63 during the period of routine 7-valent pneumococcal conjugate vaccine immunisation (May 2007-April 2010) and 41 during the period of 13-valent pneumococcal conjugate vaccine immunisation (May 2010-April 2015). When both periods were compared, a 62% (95% CI: 45-75%) decrease in the incidence of pneumococcal meningitis was observed, from 2.19 cases per 100,000 inhabitants in the PCV7 period to 0.81 per 100,000 inhabitants in the PCV13 period (p=0.0001), mainly due to an 83% (95% CI: 30-96%) reduction in cases caused by serotype 19A. Isolates not susceptible to cefotaxime (MIC>0.5μg/L) decreased from 27% to 8%, (p=0.02). Mean patient ages rose from 28.7months to 38.5months (p<0.05). Case fatality rate across both periods was 5%. An unfavourable outcome (death or neurological sequelae) occurred in 27% of patients, while the rate was similar in both periods. There was no increase in meningitis caused by pneumococcal serotypes not included in 13-valent pneumococcal conjugate vaccine throughout the years of the study. CONCLUSIONS:Immunisation with 13-valent pneumococcal conjugate vaccine has reduced the rate of pneumococcal meningitis in children less than 15years, with a near-elimination of cefotaxime-resistant isolates, but morbidity has remained unchanged. A shift of pneumococcal meningitis towards slightly higher age groups was also observed.