title: Epidemiology of serogroup C and Y invasive meningococcal disease (IMD) in Ontario, 2000-2013: Vaccine program impact assessment.
abstract: OBJECTIVE
  A publicly-funded meningococcal serogroup C conjugate vaccine (MCCV) program was introduced in Ontario, in 2004/2005 for 1-year-old children as well as adolescents (approximately 12 years old). In 2009, quadrivalent meningococcal conjugate vaccine (MCV4) replaced MCCV for grade seven students. Our objective was to determine meningococcal vaccine program impact on reported cases of serogroup C and Y invasive meningococcal disease (IMD) at the population level in Ontario, Canada.
  
  
  METHODS
  Data were obtained from the Ontario reportable diseases system, the integrated Public Health Information System (iPHIS), and Public Health Ontario Laboratories (PHOL) for 2000-2013. Descriptive epidemiologic analyses, including age-specific rates for age groups based on program eligibility, were conducted. Changes over the 14-year observation period and comparison of pre- and post-program periods for MCCV and MCV4 were assessed. Analyses were conducted using SAS 9.3.
  
  
  RESULTS
  There were 161 serogroup C IMD cases and its annual incidence decreased significantly over time (17.2% reduction per year [95% CI: 13.4 to 20.7]). The incidence of serogroup C IMD decreased significantly in children aged 1-17 years in the post-program period, based on age-specific incidence rate ratios (IRRs) and their 95% confidence intervals (CIs). Adolescents 12-16 years had the lowest serogroup C IRR (0.07 [95% CI: 0.01 to 0.55]); the rate decreased more than 14-fold between the pre- and post-periods. There were 187 serogroup Y IMD cases and there was a non-significant 1.6% reduction per year [95% CI: -1.9 to 5.1]) over the surveillance period. Likewise, there was a non-significant decrease in serogroup Y IMD among persons 12-16 years (MCV4 eligible) in the post-program period.
  
  
  CONCLUSIONS
  Reductions in serogroup C IMD among program eligible and ineligible age groups suggest both direct and indirect MCCV vaccine program impact. Continued surveillance of IMD in Ontario is important to further assess MCV4 program impact.
authors: Public Health Ontario, 480 University Avenue, Suite 300, Toronto, ON, Canada M5G 1V2; Division of Paediatric Medicine, Hospital for Sick Children, 555 University Avenue, Black Wing, 10th Floor, Toronto, ON, Canada M5G 1X8. Electronic address: anne.wormsbecker@oahpp.ca.
authors: A E
authors: AE
authors: Wormsbecker
authors: Public Health Ontario, 480 University Avenue, Suite 300, Toronto, ON, Canada M5G 1V2. Electronic address: kenny.wong@oahpp.ca.
authors: K
authors: K
authors: Wong
authors: Public Health Ontario Laboratories, 661 University Avenue, Suite 1701, Toronto, ON, Canada M5G 1M1; Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Medical Sciences Building, 1 King's College Circle, 6th Floor, Toronto, ON, Canada M5S 1A8. Electronic address: frances.jamieson@oahpp.ca.
authors: F B
authors: FB
authors: Jamieson
authors: Public Health Ontario, 480 University Avenue, Suite 300, Toronto, ON, Canada M5G 1V2; Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Medical Sciences Building, 1 King's College Circle, 6th Floor, Toronto, ON, Canada M5S 1A8; Dalla Lana School of Public Health, University of Toronto, Health Science Building, 155 College Street, 6th Floor, Toronto, ON, Canada M5T 3M7. Electronic address: natasha.crowcroft@oahpp.ca.
authors: N S
authors: NS
authors: Crowcroft
authors: Public Health Ontario, 480 University Avenue, Suite 300, Toronto, ON, Canada M5G 1V2; Dalla Lana School of Public Health, University of Toronto, Health Science Building, 155 College Street, 6th Floor, Toronto, ON, Canada M5T 3M7. Electronic address: shelley.deeks@oahpp.ca.
authors: S L
authors: SL
authors: Deeks
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D017589:Immunization Programs; D015994:Incidence; D007223:Infant; D008297:Male; D008589:Meningococcal Infections / Q000453:epidemiology* / Q000517:prevention & control; D022401:Meningococcal Vaccines / Q000627:therapeutic use*; D008875:Middle Aged; D038542:Neisseria meningitidis, Serogroup C; D038581:Neisseria meningitidis, Serogroup Y; D009864:Ontario / Q000453:epidemiology; D015397:Program Evaluation; D012307:Risk Factors; D065288:Serogroup; D018074:Vaccines, Conjugate / Q000627:therapeutic use; D055815:Young Adult
chemical_list: D022401:Meningococcal Vaccines; D018074:Vaccines, Conjugate; C410218:serogroup C meningococcal conjugate vaccine
keywords: Epidemiology; Meningococcal infections; Meningococcal vaccines; Neisseria meningitidis; Public health