The Spectrum of CNS Infections in Children and Adolescents in Denmark 2017–2023: A Multicenter Population-based Cohort Study

BACKGROUND: The epidemiology of pediatric central nervous system (CNS) infections has shifted over recent decades and remains incompletely described. We aimed to describe the incidence, etiology, age distribution and burden of pediatric CNS infections in a Danish population. METHODS: This population-based cohort study included all previously healthy Danish children 0-17 years of age in East Denmark from January 1, 2017, to December 31, 2023, with microbiologically verified CNS infections or cerebral abscess/empyema verified by imaging. RESULTS: Totally 465 patients were included. The total annual incidence per 1,000,000 was 125 (95% confidence interval [CI] 114-137), with 49 (95% CI 42-57) for viral CNS infections, 24 (95% CI 19-29) for bacterial meningitis, 7 (95% CI 5-10) for cerebral abscess/empyema and 44 (95% CI 38-51) for neuroborreliosis. Viral infections dominated in infants under 3 months (88/113, 78%) and adolescents 12-17 years (33/70, 47%), while neuroborreliosis dominated in children 1-11 years (149/255, 58%). Among 44 children 5-17 years old with bacterial infections (except neuroborreliosis), 23 (52%) had abscess/empyema and 21 (48%) bacterial meningitis. Intensive care was required in 1 (<1%) of 166 with viral meningitis/encephalitis, 21 (23%) of 90 with bacterial meningitis and 2 (7%) of 27 with abscess/empyema. Relapse occurred in 6 (7%) with bacterial meningitis and 1 (4%) with abscess/empyema. Death occurred in 5 (6%) children with bacterial meningitis. CONCLUSIONS: The pattern of pediatric CNS infections in the 2020 era calls for awareness, as neuroborreliosis was the most common disease, alongside viral infections, while cerebral abscess/empyema occurred as frequently as bacterial meningitis in school-age children. Bacterial meningitis remained associated with high morbidity and mortality.