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Canadian Vaccines: Are Canadian Kids Undervaccinated?

04/22/2013 05:11 EDT | Updated 06/22/2013 05:12 EDT
Canadian Press
TORONTO - On the face of it, it looks pretty embarrassing.

A recent UNICEF report on the well-being of children in affluent countries suggested Canada's childhood immunization rate was stunningly low — near the bottom of a list of more than 30 countries.

The report, which used data provided by the countries themselves, said only 84 per cent of Canadian children had the appropriate number of doses of vaccine for measles, polio and DPT3 — that's the three-dose diphtheria, pertussis and tetanus vaccine — for children between the ages of 12 and 23 months.

In this day and age, is it possible that 16 per cent of Canadian children are either under-vaccinated or unvaccinated? And why would Canada's rates be lower than those of Britain, the home of the modern anti-vaccination movement, or the United States, where the seeds of vaccine rejection have fallen on fertile soil?

It turns out there are really no good answers to those questions. That's because, though Canadian governments spend oodles to protect children against avoidable diseases that can sicken, maim or kill, they collectively do not gather data on the delivery of those vaccines in ways that are useful for assessing the reach and efficacy of the programs.

To put it more simply: Canada doesn't have a national vaccination registry, so no one is really sure which children have been vaccinated against which diseases. While it seems likely there are communities or neighbourhoods where clusters of unvaccinated children are like dry tinder waiting for a flying ember to ignite an outbreak — someone arriving back from abroad with measles, say — often public health officials can only really guess at where they are.

"My first reaction to the UNICEF report was: Well, how do they know? Yeah, it looks bad, but how do they know it's that low?" says Dr. Natasha Crowcroft, chief of infectious diseases at Public Health Ontario.

Crowcroft's comment serves both as a defence of the state of vaccination uptake in Canada and an indictment of the way Canadian jurisdictions record it.

The gut reaction of many involved in immunization policy in Canada is that the figure in the UNICEF report probably does not accurately reflect the immunization status of Canadian children. If rates were that low, Canada would be having more outbreaks of measles, mumps, rubella, and other vaccine-preventable diseases, they say.

"The proof of the pudding is that we're in general not getting big outbreaks. So that is reassuring... apart from the fact that in 2011 we had the biggest outbreak of measles in the whole of the Americas in Quebec," says Crowcroft.

Dr. Monika Naus, medical director of immunization programs at the B.C. Center for Disease Control, agrees.

"I don't think we are a shining light," Naus cautions.

"No matter how we crunch our data, we want to be doing much better than we are. We're not in excess of 95 per cent for any antigen by (a child's) second birthday in B.C. But I think I do wonder whether everybody calculated the numbers in exactly the same way.... Because I wouldn't have expected Canada to be third from the bottom."

Because Canada doesn't have a national vaccine registry — or even a full set of provincial and territorial registries — to draw on, when UNICEF asks Canada for immunization estimates for its report (which is issued every two years), Canada must resort to a telephone survey.

The 2009 survey, which was used for the most recent UNICEF report, was done by a commercial polling company and drew on information from 5,000 households, says Dr. John Spika, director general of the Public Health Agency of Canada's centre for immunizations and respiratory infectious diseases.

The 2011 survey, which was conducted by Statistics Canada, had a stronger methodology, Spika says. The results are still being analyzed, and he won't reveal a figure, but he says the number was better. "I can tell you that the results that we're looking at from that methodology put is clearly in the top tier of the countries that are listed."

Spika is also a bit dubious of how the data for the other countries was gathered, noting that some which have had large outbreaks of measles and other vaccine preventable diseases in recent years are well above Canada on the list.

"When you look at some of the countries that ranked higher than Canada — Romania, France, U.K., Germany, Switzerland — where have the big measles outbreaks been in the last couple of years? And Bulgaria ... their rates are 96 per cent or so. Bulgaria had a huge measles outbreak, what two, three years ago."

A decade ago, people in public health might have predicted Canada would have a better handle on childhood immunization status by now.

In the wake of the 2003 SARS outbreak, provincial and territorial governments knew they had a problem gathering key health information in ways that would allow it to be shared across borders. That had become all too apparent during SARS.

With public health needs suddenly a national priority, governments across the country talked about building a system where information could be shared across jurisdictions.

For a brief moment, it was thought the program, called Panorama, might serve as a platform for a national vaccination registry, says Spika. But Canada's decentralized health-care system got the better of those dreams. And the idea of one registry gave way to the notion of a collection of provincial and territorial registries, housed within the Panorama system.

Ten years later, that still hasn't come into being. Five provinces and one territory have some form of electronic registry, some within and others outside of the Panorama system, Spika says. Two others — Ontario and Quebec — have committed to moving towards a Panorama-compatible registry. But progress has been slow.

Part of the problem has been differences in delivery systems. In some provinces, public health nurses give the majority of childhood vaccines, making it easier to gather data. In others, children may get their shots from a family doctor, a public health nurse, a pharmacist, or at a school-based clinic. That diversity of providers may provide convenience for parents, but it's a challenge for those trying to gather data.

"I think everyone's really looking forward to an integration of immunization data that would source from whatever provider gave that vaccine — whether it's a pharmacist ... or a public health nurse or a family doctor or a First Nations health-care provider. They would be entering it into an electronic health record of some kind and it would automatically go where it needs to go," Naus says.

"That's what hasn't happened yet, anywhere, as far as I'm aware."

Why does it matter? For starters, consider the UNICEF report.

Without registries, provinces and territories cannot say for sure how many of their children are vaccinated and how many are not. Nor can they say if the vaccinated kids got their shots at the right time, or if some followed alternate schedules that appear to be growing in popularity among some vaccine-hesitant parents. Alternate schedules are not advised by the experts who recommend immunization policies.

Or consider what happened during Quebec's measles outbreak. Researchers there suspected some of the children who contracted measles had been vaccinated — in fact, had received the recommended complement of doses.

If true, that raises questions about whether there was a problem with the vaccine or whether children were being vaccinated at too young an age for the vaccine to give proper protection. But teasing out that information became a large challenge. If there had been a registry in place, it would have been far easier to determine why so many children in Quebec contracted measles in that outbreak, experts say.

Likewise, registries would help public health spot vaccine related problems, if they occur.

Crowcroft explains: "I want to be able to say hand-on-heart to someone: We know who's getting this vaccine. We know exactly what they're getting. And if something goes wrong, we'll find out about it. And without a vaccine registry, I don't know that I can really say that."

Finally, vaccine registries could help provinces save money. Naus says several provinces are interested in looking at whether the HPV vaccines, which is currently given in three doses, could be as effective with only two. That would cut a third of the cost from an expensive vaccination program. Vaccine registries could help answer that type of question, she says.