title: Changes in Meningococcal Strains in the Era of a Serogroup C Vaccination Campaign: Trends and Evolution in Belgium during the Period 1997-2012.
abstract: BACKGROUND
  Invasive meningococcal disease (IMD) is a major cause of bacterial meningitides and septicaemia. This study shows the results of the laboratory-based surveillance of IMD in Belgium over the period 1997-2012.
  
  
  METHODS
  The results are based on microbiological and molecular laboratory surveillance of 2997 clinical isolates of N. meningitides received by the Belgian Meningococcal Reference Centre (BMRC) over the period 1997-2012.
  
  
  RESULTS
  Serogroup B has always been a major cause of meningococcal disease in Belgium, with P3.4 as most frequent serotype till 2008, while an increase in non-serotypable strains has been observed in the last few years. Clonal complexes cc-41/44 and cc-269 are most frequently observed in serogroup B strains. In the late nineties, the incidence of serogroup C disease increased considerably and peaked in 2001, mainly associated with phenotypes C:2a:P1.5,2, C:2a:P1.5 and C:2a:P1.2 (ST-11/ET-37 clonal complex). The introduction of the meningococcal C conjugate vaccine has been followed by an 88% significant decrease in serogroup C disease from 2001 to 2004 nationally, yet sharper in Flanders (92%) compared to Wallonia (77%). Since 2008 a difference in incidence of serogroup C was observed in Flanders (0-0.1/100,000) versus Wallonia (0.1-0.3/100,000).
  
  
  CONCLUSIONS
  This study showed the change in epidemiology and strain population over a 16 years period spanning an exhaustive vaccination campaign and highlights the influence of regional vaccination policies with different cohorts sizes on short and long-term IMD incidences.
authors.affiliation: Sections of Bacterial Diseases, Scientific Institute of Public Health, Brussels, Belgium.
authors.forename: Wesley
authors.initials: W
authors.lastname: Mattheus
authors.affiliation: Medical Epidemiologist, Health Care Knowledge Centre, Brussels, Belgium.
authors.forename: Germaine
authors.initials: G
authors.lastname: Hanquet
authors.affiliation: Sections of Bacterial Diseases, Scientific Institute of Public Health, Brussels, Belgium.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Collard
authors.affiliation: Sections of Bacterial Diseases, Scientific Institute of Public Health, Brussels, Belgium.
authors.forename: Raymond
authors.initials: R
authors.lastname: Vanhoof
authors.affiliation: Sections of Bacterial Diseases, Scientific Institute of Public Health, Brussels, Belgium.
authors.forename: Sophie
authors.initials: S
authors.lastname: Bertrand
mesh_terms: D000293:Adolescent; D000328:Adult; D001530:Belgium / Q000453:epidemiology; D005075:Biological Evolution; D002648:Child; D002675:Child, Preschool; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008589:Meningococcal Infections / Q000453:epidemiology* / Q000382:microbiology / Q000401:mortality / Q000517:prevention & control; D022401:Meningococcal Vaccines / Q000627:therapeutic use*; D058885:Multilocus Sequence Typing; D038542:Neisseria meningitidis, Serogroup C / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D010641:Phenotype; D011379:Prognosis; D065288:Serogroup; D015996:Survival Rate; D013997:Time Factors; D014611:Vaccination / Q000401:mortality*; D055815:Young Adult
chemical_list: D004269:DNA, Bacterial; D022401:Meningococcal Vaccines; C410218:serogroup C meningococcal conjugate vaccine