title: Bacterial meningitis in adults in Iceland, 1995-2010.
abstract: BACKGROUND
  Bacterial meningitis is a serious disease with a mortality rate of 15-20% in adults. We conducted a population-based study of bacterial meningitis in adults (≥ 16 y) in Iceland, 1995-2010.
  
  
  METHODS
  Cases were identified based on positive bacterial cultures from cerebrospinal fluid (CSF) and/or the ICD codes for bacterial meningitis. Medical charts were reviewed and outcomes were assessed using the national population registry. The study period was divided into 2 equal parts, 1995-2002 and 2003-2010, before and after implementation of routine childhood vaccination against serogroup C meningococci, respectively.
  
  
  RESULTS
  In total, 111 episodes occurred in 110 individuals. The most common causative organisms were Neisseria meningitidis (41%) and Streptococcus pneumoniae (30%). Only 30% of the patients presented with the classical symptom triad of fever, neck stiffness, and an altered mental status. The overall incidence was 3.2/100,000 inhabitants/y, and dropped significantly between the first and second halves of the study (p = 0.03). This drop was due to a reduced incidence of N. meningitidis meningitis: 34 and 12 cases in the first and second periods, respectively (p = 0.006). The incidence of meningitis caused by S. pneumoniae remained unchanged. The case fatality rates were 18% and 13% in the first and second halves of the study, respectively (difference not significant).
  
  
  CONCLUSIONS
  The incidence of bacterial meningitis has decreased since the implementation of meningococcal C vaccination in 2002. However, the case fatality rate has remained unchanged.
authors.affiliation: From the Faculty of Medicine, University of Iceland , Reykjavik , Iceland.
authors.forename: Asgerður
authors.initials: A
authors.lastname: Thornórðardóttir
authors.forename: Helga
authors.initials: H
authors.lastname: Erlendsdóttir
authors.forename: Bryndís
authors.initials: B
authors.lastname: Sigurðardóttir
authors.forename: Hjördís
authors.initials: H
authors.lastname: Harðardóttir
authors.forename: Ingi Karl
authors.initials: IK
authors.lastname: Reynisson
authors.forename: Magnús
authors.initials: M
authors.lastname: Gottfreðsson
authors.forename: Sigurður
authors.initials: S
authors.lastname: Guðmundsson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007055:Iceland / Q000453:epidemiology; D008297:Male; D016920:Meningitis, Bacterial / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology; D008875:Middle Aged; D009345:Neisseria meningitidis / Q000302:isolation & purification; D011008:Pneumococcal Infections / Q000175:diagnosis / Q000453:epidemiology; D012189:Retrospective Studies; D013296:Streptococcus pneumoniae / Q000302:isolation & purification; D055815:Young Adult