Background
The epidemiology and treatment of pneumococcal meningitis has changed with the implementation of conjugate vaccines and the introduction of adjunctive dexamethasone therapy.
Methods
We analysed episodes of community-acquired pneumococcal meningitis in adults (≥16 years) in the Netherlands, identified by the National Reference Laboratory for Bacterial Meningitis or treating physician between Oct 1, 1998 and Apr 1, 2002 and between Jan 1, 2006 and July 1, 2018. We studied incidence, pneumococcal serotypes and clinical features. Predictors for unfavourable outcome (Glasgow Outcome Scale score 1-4) were identified in a multivariable logistic regression model. Two physicians independently categorized causes of death as neurological or systemic.
Results
There were 1816 episodes in 1783 patients. The incidence of 7- and 10-7-valent pneumococcal conjugate vaccine serotypes decreased (0.42 to 0.06, p=0.001 and 0.12 to 0.03 episodes per 100,000 population per year, p=0.014). Incidence of non-vaccine serotypes increased (0.45 to 0.68, p=0.005). The use of adjunctive treatment with dexamethasone increased and was administered in 85% of patients in 2018. In-hospital death occurred in 363 episodes (20%) and unfavourable outcome in 772 episodes (43%). Delayed cerebral thrombosis occurred in 29 patients (2%) of whom 15 patients (52%) died. Adjunctive dexamethasone therapy was associated with favourable outcome (adjusted odds ratio 2.27, p<0.001), individual pneumococcal serotypes were not.
Conclusion
Implementation of conjugate vaccines and adjunctive dexamethasone therapy have changed the incidence and outcome of pneumococcal meningitis in adults over the last two decades. Despite recent advances pneumococcal meningitis remains associated with a residual high rate of mortality and morbidity.