Abstract
ObjectiveTo describe the recent trends in the burden of disease and mortalityassociated with vaccine preventable diseases (VPDs).IntroductionVaccination is one of the most successful public healthinterventions. Despite this, there are a variety of reasons that VPDscontinue to be seen in developed countries such as Canada. Thisanalysis describes the recent trends in the burden of disease andmortality associated with VPDs for which publicly funded vaccinationprograms for infants or children are implemented across the countryand for which national surveillance data are available.MethodsSurveillance data on VPDs were obtained from the CanadianNotifiable Disease Surveillance System. Population and death datawere obtained from Statistics Canada. Death data were only availableto 2012. In total, 11 VPDs have been included in the analysesnamely tetanus, diphtheria, pertussis, polio, haemophilus influenza(Hi), measles, mumps, rubella, congenital rubella syndrome (CRS),invasive meningococcal disease (IMD), invasive pneumococcaldisease (IPD). Exclusion of non-vaccine preventable serotypes fromeither data source was not possible. Analyses included incidence rate,proportion, mortality rate and risk ratio.ResultsSurveillance data indicate that from 2010 to 2014, an average of6,020 cases of VPDs were reported annually, representing an averageannual crude incidence rate of 17.3 cases per 100,000 population.VPDs accounting for the largest proportion of reported cases includeIPD (54.4%) and pertussis (29.6%). Age groups most affected includechildren less than 1 year of age (92.6 cases per 100,000) and childrenbetween 1 and 4 years of age (36.0 cases per 100,000). Age groupsleast affected include adults between 20 and 24 years old (6.9 casesper 100,000 population) and between 25 and 29 years old (7.3 casesper 100,000 population). Age groups affected differed by VPD.Death data indicate that from 2010 to 2012, VPDs accountingfor the largest proportion of deaths across all ages include IPD(58.2%), Hi (16.3%) and IMD (15.3%). Youth aged 19 years andunder accounted for 26.1% of VPDs deaths (mortality rate of 0.17 per100,000 population). Children less than one year old have the highestmortality rate due to VPDs (2.0 per 100,000 population) and were26.9 times more likely to die from VPDs compared to children between1 and 19 years of age. Adults aged 20 years and older accounted for73.9% of VPD deaths (mortality rate of 0.14 per 100,000 population).A high mortality rate was also seen in adults 60 year old and over(0.3 per 100,000 population); adults 60 years old and over were more2.6 times more likely to die from VPDs compared to adults between20 and 59 years old.ConclusionsThe results of routine Canadian surveillance data suggest thatdespite high vaccine coverage rates generally seen in developedcountries such as Canada, a possible preventable burden of illnessdue to VPDs still occurs across all age groups. Consideration ofVPDs as a whole allows a real appreciation of the burden and deathsassociated with VPDs in general. The analysis has shown that whilethe incidence rates are highest among children 4 years old andyounger, mortality due to VPDs continues to occur and primarilyaffects infants and elderly. Due to the asymptomatic nature of someVPDs and data limitations, reported cases are likely underestimatesof the true burden.