A mass immunization campaign was implemented in 2001 to control a serogroup C meningococcal disease outbreak, and a newly licensed serogroup C meningococcal conjugate vaccine (C-MCV) was used. In 2002, 1 C-MCV dose was routinely offered to children 12 months of age.
To assess the epidemiologic effect of the campaign and C-MCV effectiveness during a 7-year period according to age at vaccination and delay since vaccine administration.
Cases of invasive meningococcal infection reported to public health authorities and the reference laboratory during the period 1990 to 2008 were obtained to calculate year- and age-specific incidence rates. Multiple sources were used to ascertain the immunization status of cases. Immunization registry data were used to estimate age-specific C-MCV uptake rates in different birth cohorts. Vaccine effectiveness was estimated by Mantel–Haenszel method and logistic regression models.
After mass immunization campaign, meningococcal C disease incidence decreased markedly not only in highly vaccinated but also in poorly vaccinated and nonvaccinated birth cohorts. Overall vaccine effectiveness was 87.4% (95% CI: 75.4%–94.2%) with lower protection in children vaccinated <2 years of age and waning of protection of higher magnitude in this age group.
Results support the current Canadian recommendation to provide booster vaccination for adolescents.
SUPPLEMENTAL DIGITAL CONTENT IS AVAILABLE IN THE TEXT.
From the *Department of Social and Preventive Medicine, Laval University, Quebec City, Canada; †Quebec University Hospital Research Centre, Quebec City, Canada; ‡Quebec National Public Health Institute, Quebec City, Canada; and §Quebec Public Health Laboratory, Quebec National Public Health Institute, Montreal, Canada.
Accepted for publication December 29, 2010.
Supported by a grant from the Quebec Ministry of Health and Social Services; research grants, honoraria, and reimbursements of travel expenses from vaccine manufacturers including Glaxo-Smith-Kline, Novartis, Sanofi Pasteur, Merck and Pfizer (to P.D.W.); research grants from Sanofi Pasteur and Chiron (now Novartis) (to G.D.S.); and research grants from Sanofi Pasteur and GlaxoSmithKline (to N.B.).
Address for correspondence: Philippe De Wals, MD, PhD, Département de Médecine sociale et préventive, Université Laval, Pavillon Ferdinand-Vandry, 1050 Avenue de la Médecine, Québec (QC), G1V 0A6, Canada. E-mail: firstname.lastname@example.org.
Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (www.pidj.com).