Characteristics and outcomes of patients with pneumococcal meningitis in the light of different vaccination policies and Covid measures

Background and rationale: Streptococcus pneumoniae is the most prevalent pathogen causing bacterial meningitis. Invasive pneumococcal disease (IPD) includes PM, which has distinct epidemiological and pathophysiological characteristics compared to sepsis or pneumonia. PM leads to death in 15% and to long-term sequalae in one third of survivors. Vaccines cover up to 23 of over 100 pneumococcal serotypes. Vaccination policies differ between countries, e.g., the Netherlands and Switzerland, and serotype replacement has begun to counterbalance the initial decrease of IPD incidence observed after introduction of paediatric pneumococcal conjugate vaccines (PCV). Implementation of Covid measures has reduced the incidence of communicable diseases, including IPD. How these different developments affect patient characteristics and outcomes is unclear.Overall objectives: To evaluate the long-term effect of differing pneumococcal vaccination policies and Covid measures on patient characteristics and outcomes of PM.Specific aims: 1) To review European vaccination programs and vaccination coverage on PM and assess correlations with patient characteristics and outcomes. 2) To evaluate if patient characteristics and outcomes in Switzerland and the Netherlands, which have differing vaccination policies, vary. 3) To evaluate if patient characteristics and outcomes in the two countries changed before, during and after Covid measures.Methods: 1) European pneumococcal vaccination programs will be reviewed systematically and analysed for correlation with characteristics and outcomes of patients with PM.2) Data from the Swiss and Dutch mandatory surveillance and the Dutch nation-wide cohort study on bacterial meningitis will be searched for adults with PM. ?2-test will be used to identify differences in patient characteristics and outcomes between the Dutch and Swiss cohort.3) To compare incidence before, during, and after Covid measures based on the Oxford stringency index, we will estimate incidence rate ratios. Differences in serotypes and patient characteristics and outcomes will be tested using a ?2-test.Expected results: We expect that differing vaccination policies and Covid measures significantly affect patient characteristics and outcomes.Impact: Knowledge on the changing epidemiology of PM will influence policy making in terms of surveillance and vaccination strategies.