Children in some local health areas of Metro Vancouver have much lower vaccination rates than others, according to a recent University of British Columbia study.
By examining Vancouver Coastal Health data on kindergarten vaccination rates for the 2013-14 school year, researchers from the departments of sociology and pediatrics discovered vaccination rates varied by as much as 30 per cent between local health areas.
Researchers used the city of Richmond, which has vaccination rates greater than 90 per cent, as a baseline. Compared to Richmond, West Vancouver/Bowen Island's rates were 30 percentage points lower; North Vancouver's were almost 20 percentage points lower; and the Downtown Eastside's were 12 percentage points lower. And when analyzed by school type, researchers found kindergarten vaccine coverage in private, non-religious schools was 10 per cent lower than in public schools.
"Our study found some of the lowest vaccination rates were in more affluent locations, like North and West Vancouver," said lead author Richard Carpiano, professor of sociology. "In the United States, child immunization rates don't follow the typical variations that you see for other types of health disparities, and our findings seem to be consistent with what's been observed south of the border."
Immunization rates of 90 per cent or above are needed to achieve "herd immunity" for a community, or school. The clustering of unvaccinated children is a public-health concern, said the researchers.
"If you have a school where only ten per cent of the kids are immunized, there's no herd immunity in that school," said co-author Julie Bettinger, associate professor in the department of pediatrics and an investigator at BC Children's Hospital.
One approach that could be considered is mandatory immunizations for school entry, which has been implemented in Ontario, New Brunswick and California. "There isn't a requirement for mandatory immunization in B.C.," said Bettinger. "There's been a lot of conversation in public health about whether that should change."
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"Vaccine coverage for kindergartners: Factors associated with school and area variation in Vancouver, British Columbia" appears in Vaccine Reports: http://www.sciencedirect.com/science/article/pii/S1879437816300225
Journal
Vaccine Reports