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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

Number and incidence (per 100,000) of IMD and by serogroup B, Ontario, Canada, 2000–2010. The number of cases (solid bars) and annual incidence per 100,000 population per year (lines) for invasive meningococcal disease in Ontario, Canada, overall (all causes; N = 713) and by serogroup B (n = 259) in Ontario, Canada, from 2000 to 2010. IMD caused by other than serogroup B includes A, C, Y, W135, non-groupable and unknown.
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Figure 1: Number and incidence (per 100,000) of IMD and by serogroup B, Ontario, Canada, 2000–2010. The number of cases (solid bars) and annual incidence per 100,000 population per year (lines) for invasive meningococcal disease in Ontario, Canada, overall (all causes; N = 713) and by serogroup B (n = 259) in Ontario, Canada, from 2000 to 2010. IMD caused by other than serogroup B includes A, C, Y, W135, non-groupable and unknown.

Mentions: Figure 1 shows the total number of IMD cases (overall and serogroup B) and incidence rates between 2000 and 2010. The annual incidence of serogroup B disease ranged between 0.11 per 100,000 population in 2010 and 0.27 per 100,000 population in 2007. This is in contrast to the annual rates of overall IMD which ranged between 0.26 in 2010 and 0.94 in 2001 per 100,000 population. While the incidence of overall IMD has decreased over time since its peak in 2001, there was no discernible change in the incidence of serogroup B disease over time.


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)

Number and incidence (per 100,000) of IMD and by serogroup B, Ontario, Canada, 2000–2010. The number of cases (solid bars) and annual incidence per 100,000 population per year (lines) for invasive meningococcal disease in Ontario, Canada, overall (all causes; N = 713) and by serogroup B (n = 259) in Ontario, Canada, from 2000 to 2010. IMD caused by other than serogroup B includes A, C, Y, W135, non-groupable and unknown.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 1: Number and incidence (per 100,000) of IMD and by serogroup B, Ontario, Canada, 2000–2010. The number of cases (solid bars) and annual incidence per 100,000 population per year (lines) for invasive meningococcal disease in Ontario, Canada, overall (all causes; N = 713) and by serogroup B (n = 259) in Ontario, Canada, from 2000 to 2010. IMD caused by other than serogroup B includes A, C, Y, W135, non-groupable and unknown.
Mentions: Figure 1 shows the total number of IMD cases (overall and serogroup B) and incidence rates between 2000 and 2010. The annual incidence of serogroup B disease ranged between 0.11 per 100,000 population in 2010 and 0.27 per 100,000 population in 2007. This is in contrast to the annual rates of overall IMD which ranged between 0.26 in 2010 and 0.94 in 2001 per 100,000 population. While the incidence of overall IMD has decreased over time since its peak in 2001, there was no discernible change in the incidence of serogroup B disease over time.

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