Dear Editors,
We are writing to correct a number of inaccuracies regarding the epidemiology of invasive meningococcal disease and meningococcal immunization programs in Canada as reported by Baccarini et al. in the January 2013 issue.
(1) Three surveillance systems exist for invasive meningococcal disease in Canada: the Notifiable Diseases Surveillance as mentioned by Baccarini is just one. The Canadian Immunization Monitoring Program Active (IMPACT) and the International Circumpolar Surveillance (ICS) system also monitor IMD in Canada. IMPACT is an active, population-based sentinel surveillance system that monitors IMD in 50% of the Canadian population. Since 2002, this surveillance has captured laboratory confirmed hospital admissions in adults and children from defined population areasCitation1,Citation2 across Canada. As well, it captures isolates from all cases, which are then typed at the National Microbiology Laboratory in Winnipeg. ICS is a passive surveillance system that has captured IMD cases occurring in the far north (above 60 degrees latitude) since 2000.Citation3
(2) While some of the recent declines in serogroup C disease in Canada may be attributable to mass immunization campaigns in 2001, those campaigns were initiated in only 2 provinces and cannot account for all of the decrease. Rather the declines are more likely related to the universal infant serogroup C conjugate immunization programs and adolescent catch-up programs that started as early as 2001–2002 in some provinces.Citation2,Citation4
(3) While it is true the incidence of serogroup C has declined dramatically in Canada, the incidence of other serogroups has not declined. In fact in some provinces, the incidence of serogroup B has actually increased since the introduction of serogroup C conjugate immunization programs.Citation5 In other provinces, the incidence of disease continues to exhibit cyclical patterns, but nowhere have we observed a decline in serogroups B, Y and W135.Citation2,Citation6,Citation7
(4) The use of vaccination: Canada has been pro-active in its control of IMD. Universal meningococcal immunization programs are administered to infants and adolescents in all provinces and territories. The use of monovalent or quadravalent vaccine in the various provincial adolescent programs is determined by local epidemiology. While coverage data are always difficult to obtain in Canada, based on available data, the uptake of monovalent and quadravalent vaccine among adolescents in Canada has been much higher than in the United States. Recent figures from British Columbia and Manitoba indicate a rate of 80–90% among adolescents.Citation8,Citation9 This difference in uptake between the US and Canada is likely due to the mode of delivery. Meningococcal vaccines are administered to older children and adolescents as part of school-based programs and do not rely on physician delivery.
Given the differences in meningococcal epidemiology and control strategies between the United States and Canada, we hope our letter provides the reader with a better understanding of Canadian meningococcal disease epidemiology.
Regards,
Dr Julie A. Bettinger, Dr David W. Scheifele, Dr Scott A. Halperin· Dr Wendy Vaudry, Dr Nicole Le Saux
References
- Le Saux N, Bettinger JA, Wootton S, Halperin SA, Vaudry W, Scheifele DW, et al. Profile of serogroup Y meningococcal infections in Canada: Implications for vaccine selection. Can J Infect Dis Med Microbiol 2009; 20:e130 - 4; PMID: 21119789
- Bettinger JA, Scheifele DW, Le Saux N, Halperin SA, Vaudry W, Tsang R, Canadian Immunization Monitoring Program, Active (IMPACT). The impact of childhood meningococcal serogroup C conjugate vaccine programs in Canada. Pediatr Infect Dis J 2009; 28:220 - 4; http://dx.doi.org/10.1097/INF.0b013e31819040e7; PMID: 19209096
- Parkinson AJ, Bruce MG, Zulz T. International Circumpolar Surveillance, an Arctic network for the surveillance of infectious diseases. Emerg Infect Dis 2008; 14:18 - 24; http://dx.doi.org/10.3201/eid1401.070717; PMID: 18258072
- Kinlin LM, Jamieson F, Brown EM, Brown S, Rawte P, Dolman S, et al. Rapid identification of herd effects with the introduction of serogroup C meningococcal conjugate vaccine in Ontario, Canada, 2000-2006. Vaccine 2009; 27:1735 - 40; http://dx.doi.org/10.1016/j.vaccine.2009.01.026; PMID: 19186206
- Gilca R, Deceuninck G, Lefebvre B, Tsang R, Amini R, Gilca V, et al. The changing epidemiology of meningococcal disease in Quebec, Canada, 1991-2011: potential implications of emergence of new strains. PLoS One 2012; 7:e50659; http://dx.doi.org/10.1371/journal.pone.0050659; PMID: 23209803
- Bettinger JA, Scheifele DW, Le Saux N, Halperin SA, Vaudry W, Tsang R, Members of Canadian Immunization Monitoring Program, Active (IMPACT). The disease burden of invasive meningococcal serogroup B disease in Canada. Pediatr Infect Dis J 2013; 32:e20 - 5; http://dx.doi.org/10.1097/INF.0b013e3182706b89; PMID: 22926207
- Dang V, Jamieson FB, Wilson S, Rawte P, Crowcroft NS, Johnson K, et al. Epidemiology of serogroup B invasive meningococcal disease in Ontario, Canada, 2000 to 2010. BMC Infect Dis 2012; 12:202; http://dx.doi.org/10.1186/1471-2334-12-202; PMID: 22928839
- British Columbia Centre for Disease Control Grade 6 Students with Up-to-date Immunizations. <http://www.bccdc.ca/NR/rdonlyres/BDD8BBD7-2C78-4369-B5B1-69D4B039BC3D/0/_Public_Grade6Results_2011.pdf> Accessed Jan. 2013.
- Manitoba Immunization Monitoring System 2010 Report. <http://digitalcollection.gov.mb.ca/awweb/pdfopener?smd=1&did=20457&md=1> Accessed Jan. 2013.