Effectiveness of a mass immunization campaign using serogroup C meningococcal conjugate vaccine.
BACKGROUND
Meningococcal polysaccharide vaccines are of limited effectiveness. New protein-polysaccharide conjugate vaccines have yet to be evaluated in field conditions.


OBJECTIVE
To assess the effectiveness of a serogroup C conjugate meningococcal vaccine in an outbreak setting.


METHODS
Population-based observational study of cases of invasive serogroup C meningococcal disease from 1996 through 2002 in Quebec identified from the provincial registry of notifiable diseases and from the provincial reference laboratory. In 2001, a mass immunization campaign with a conjugate vaccine was conducted to control an emerging epidemic. The number of vaccinated individuals was extracted from meningococcal immunization registries.


METHODS
Incidence of invasive meningococcal disease before and 1 year after the campaign in vaccinated and unvaccinated individuals.


RESULTS
Vaccination coverage of those 2 months to 20 years was 82.1%. After the campaign, the number of cases of serogroup C disease decreased from 58 in 2001 to 27 in 2002, and the incidence from 7.8 per million to 3.6 per million. Vaccine effectiveness was found to be 96.8% (95% confidence interval, 75.0%-99.9%). There was no observed increase in the incidence of the other serogroups.


CONCLUSIONS
The new conjugate vaccine was effective in controlling an emerging epidemic of serogroup C meningococcal disease, as well as providing short-term protection across a wide age range.
De Wals
Philippe
P
Quebec National Public Health Institute and Department of Preventive and Social Medicine, Laval University, Quebec City, Quebec. Philippe.De.Wals@ssss.gouv.qc.ca
Deceuninck
Geneviève
G
Boulianne
Nicole
N
De Serres
Gaston
G
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D006801:Humans; D015994:Incidence; D007223:Infant; D032541:Mass Vaccination; D008589:Meningococcal Infections / Q000453:epidemiology* / Q000517:prevention & control*; D022401:Meningococcal Vaccines / Q000008:administration & dosage*; D038542:Neisseria meningitidis, Serogroup C; D011792:Quebec / Q000453:epidemiology
D022401:Meningococcal Vaccines; C410218:serogroup C meningococcal conjugate vaccine