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Epidemiology of serogroup B invasive meningococcal disease in Ontario, Canada, 2000 to 2010.

Dang V, Jamieson FB, Wilson S, Rawte P, Crowcroft NS, Johnson K, Tsang RS, Deeks SL - BMC Infect. Dis. (2012)

Bottom Line: We calculated a crude number needed to vaccinate using the inverse of the infant (<1 year) age-specific incidence multiplied by expected vaccine efficacies between 70% and 80%, and assuming only direct protection (no herd effects).Although rare, the proportion of IMD caused by serogroup B has increased and currently causes most IMD in Ontario, with infants having the highest risk of disease.Although serogroup B meningococcal vaccines are highly anticipated, our findings suggest that decisions regarding publicly funding serogroup B meningococcal vaccines will be difficult and may not be based on disease burden alone.

View Article: PubMed Central - HTML - PubMed

Affiliation: Public Health Ontario, Toronto, ON, Canada.

ABSTRACT

Background: Invasive meningococcal disease (IMD) caused by serogroup B is the last major serogroup in Canada to become vaccine-preventable. The anticipated availability of vaccines targeting this serogroup prompted an assessment of the epidemiology of serogroup B disease in Ontario, Canada.

Methods: We retrieved information on confirmed IMD cases reported to Ontario's reportable disease database between January 1, 2000 and December 31, 2010 and probabilistically-linked these cases to Public Health Ontario Laboratory records. Rates were calculated with denominator data obtained from Statistics Canada. We calculated a crude number needed to vaccinate using the inverse of the infant (<1 year) age-specific incidence multiplied by expected vaccine efficacies between 70% and 80%, and assuming only direct protection (no herd effects).

Results: A total of 259 serogroup B IMD cases were identified in Ontario over the 11-year period. Serogroup B was the most common cause of IMD. Incidence ranged from 0.11 to 0.27/100,000/year, and fluctuated over time. Cases ranged in age from 13 days to 101 years; 21.4% occurred in infants, of which 72.7% were <6 months. Infants had the highest incidence (3.70/100,000). Case-fatality ratio was 10.7% overall. If we assume that all infant cases would be preventable by vaccination, we would need to vaccinate between 33,784 and 38,610 infants to prevent one case of disease.

Conclusions: Although rare, the proportion of IMD caused by serogroup B has increased and currently causes most IMD in Ontario, with infants having the highest risk of disease. Although serogroup B meningococcal vaccines are highly anticipated, our findings suggest that decisions regarding publicly funding serogroup B meningococcal vaccines will be difficult and may not be based on disease burden alone.

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Related in: MedlinePlus

Annualized age-specific incidence for serogroup B IMDa, Ontario, Canada, 2000–2010 (N = 257). Annualized age-specific incidence per 100,000 population for serogroup B invasive meningococcal disease (IMD) in Ontario, Canada, for 2000 to 2010. aTwo serogroup B IMD cases were excluded from analysis because of missing age information.
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Figure 3: Annualized age-specific incidence for serogroup B IMDa, Ontario, Canada, 2000–2010 (N = 257). Annualized age-specific incidence per 100,000 population for serogroup B invasive meningococcal disease (IMD) in Ontario, Canada, for 2000 to 2010. aTwo serogroup B IMD cases were excluded from analysis because of missing age information.

Mentions: As there was no statistically significant difference in median age over the 11-year period, and given the small number of cases, we determined annualized incidence rates by age between 2000 and 2010 (Figure 3). Infants less than 1 year of age had the highest rate at 3.70 per 100,000 population, followed by children aged 1 to 4 years.


Epidemiology of serogroup B invasive meningococcal disease in Ontario, Canada, 2000 to 2010.

Dang V, Jamieson FB, Wilson S, Rawte P, Crowcroft NS, Johnson K, Tsang RS, Deeks SL - BMC Infect. Dis. (2012)

Annualized age-specific incidence for serogroup B IMDa, Ontario, Canada, 2000–2010 (N = 257). Annualized age-specific incidence per 100,000 population for serogroup B invasive meningococcal disease (IMD) in Ontario, Canada, for 2000 to 2010. aTwo serogroup B IMD cases were excluded from analysis because of missing age information.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472197&req=5

Figure 3: Annualized age-specific incidence for serogroup B IMDa, Ontario, Canada, 2000–2010 (N = 257). Annualized age-specific incidence per 100,000 population for serogroup B invasive meningococcal disease (IMD) in Ontario, Canada, for 2000 to 2010. aTwo serogroup B IMD cases were excluded from analysis because of missing age information.
Mentions: As there was no statistically significant difference in median age over the 11-year period, and given the small number of cases, we determined annualized incidence rates by age between 2000 and 2010 (Figure 3). Infants less than 1 year of age had the highest rate at 3.70 per 100,000 population, followed by children aged 1 to 4 years.

Bottom Line: We calculated a crude number needed to vaccinate using the inverse of the infant (<1 year) age-specific incidence multiplied by expected vaccine efficacies between 70% and 80%, and assuming only direct protection (no herd effects).Although rare, the proportion of IMD caused by serogroup B has increased and currently causes most IMD in Ontario, with infants having the highest risk of disease.Although serogroup B meningococcal vaccines are highly anticipated, our findings suggest that decisions regarding publicly funding serogroup B meningococcal vaccines will be difficult and may not be based on disease burden alone.

View Article: PubMed Central - HTML - PubMed

Affiliation: Public Health Ontario, Toronto, ON, Canada.

ABSTRACT

Background: Invasive meningococcal disease (IMD) caused by serogroup B is the last major serogroup in Canada to become vaccine-preventable. The anticipated availability of vaccines targeting this serogroup prompted an assessment of the epidemiology of serogroup B disease in Ontario, Canada.

Methods: We retrieved information on confirmed IMD cases reported to Ontario's reportable disease database between January 1, 2000 and December 31, 2010 and probabilistically-linked these cases to Public Health Ontario Laboratory records. Rates were calculated with denominator data obtained from Statistics Canada. We calculated a crude number needed to vaccinate using the inverse of the infant (<1 year) age-specific incidence multiplied by expected vaccine efficacies between 70% and 80%, and assuming only direct protection (no herd effects).

Results: A total of 259 serogroup B IMD cases were identified in Ontario over the 11-year period. Serogroup B was the most common cause of IMD. Incidence ranged from 0.11 to 0.27/100,000/year, and fluctuated over time. Cases ranged in age from 13 days to 101 years; 21.4% occurred in infants, of which 72.7% were <6 months. Infants had the highest incidence (3.70/100,000). Case-fatality ratio was 10.7% overall. If we assume that all infant cases would be preventable by vaccination, we would need to vaccinate between 33,784 and 38,610 infants to prevent one case of disease.

Conclusions: Although rare, the proportion of IMD caused by serogroup B has increased and currently causes most IMD in Ontario, with infants having the highest risk of disease. Although serogroup B meningococcal vaccines are highly anticipated, our findings suggest that decisions regarding publicly funding serogroup B meningococcal vaccines will be difficult and may not be based on disease burden alone.

Show MeSH
Related in: MedlinePlus