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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

Age distribution of serogroup B IMD cases, Ontario, Canada, 2000–2010 (N = 257). Proportion (%) of serogroup B invasive meningococcal disease (IMD) cases by age group (N = 257) and number of infant serogroup B IMD cases by age (months) (N = 55) in Ontario, Canada, from 2000 to 2010. Two serogroup B IMD cases were excluded from analysis because of missing age information.
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Figure 2: Age distribution of serogroup B IMD cases, Ontario, Canada, 2000–2010 (N = 257). Proportion (%) of serogroup B invasive meningococcal disease (IMD) cases by age group (N = 257) and number of infant serogroup B IMD cases by age (months) (N = 55) in Ontario, Canada, from 2000 to 2010. Two serogroup B IMD cases were excluded from analysis because of missing age information.

Mentions: Of the serogroup B IMD cases with known sex information (256/259, 98.8%), 55.1% of the cases occurred in males with no significant variation over time (p = 0.32). The ages of serogroup B cases ranged between 13 days and 101 years, with a median age of 17 years. Although not a statistically significant change (p = 0.40), the median age increased from 5 years in 2000 to 20 years in 2010. The proportion of children (0–18 years) compared to adults (≥19 years) has decreased over the surveillance period from 70.0% in 2000 to 50.0% in 2010 (p = 0.03). Figure 2 shows the proportion of serogroup B cases in Ontario by age. Overall, 21% of cases occurred in infants less than 1 year of age (55 cases) and 16% occurred in young children aged 1 to 4 years (41 cases). By comparison, infants and children aged 1 to 4 years represented only 1.1% and 4.3% of Ontario’s population, respectively, in 2010. Most of the infant cases (72.7%) occurred in infants less than 6 months of age.


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)

Age distribution of serogroup B IMD cases, Ontario, Canada, 2000–2010 (N = 257). Proportion (%) of serogroup B invasive meningococcal disease (IMD) cases by age group (N = 257) and number of infant serogroup B IMD cases by age (months) (N = 55) in Ontario, Canada, from 2000 to 2010. Two 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 2: Age distribution of serogroup B IMD cases, Ontario, Canada, 2000–2010 (N = 257). Proportion (%) of serogroup B invasive meningococcal disease (IMD) cases by age group (N = 257) and number of infant serogroup B IMD cases by age (months) (N = 55) in Ontario, Canada, from 2000 to 2010. Two serogroup B IMD cases were excluded from analysis because of missing age information.
Mentions: Of the serogroup B IMD cases with known sex information (256/259, 98.8%), 55.1% of the cases occurred in males with no significant variation over time (p = 0.32). The ages of serogroup B cases ranged between 13 days and 101 years, with a median age of 17 years. Although not a statistically significant change (p = 0.40), the median age increased from 5 years in 2000 to 20 years in 2010. The proportion of children (0–18 years) compared to adults (≥19 years) has decreased over the surveillance period from 70.0% in 2000 to 50.0% in 2010 (p = 0.03). Figure 2 shows the proportion of serogroup B cases in Ontario by age. Overall, 21% of cases occurred in infants less than 1 year of age (55 cases) and 16% occurred in young children aged 1 to 4 years (41 cases). By comparison, infants and children aged 1 to 4 years represented only 1.1% and 4.3% of Ontario’s population, respectively, in 2010. Most of the infant cases (72.7%) occurred in infants less than 6 months of age.

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