Kids in North Peace schools are vaccinated for measles, mumps and rubella at a significantly higher rate than their peers south of the river, according to health authority statistics.
School District 59 had an MMR vaccination rate of 85 per cent last year — the lowest of the three Northeast school districts.
Ninety-one per cent of Peace River North kindergartners had the vaccine, while 97 per cent of kids entering Fort Nelson schools were vaccinated.
Overall, 89 per cent of Northeast kindergartners were fully up to date on their MMRs during the last school year, the Northern Health data shows.
The rates measure the percentage of children who have both the MMR vaccination and booster shot by the end of their kindergarten year.
Overall, kindergartners in Northeast B.C. are vaccinated at roughly the same rate as their peers in the rest of the province.
With the exception of Fort Nelson, those rates are below what's recommended for population-wide immunity, according to two University of B.C. immunologists.
"For a community to be protected against a measles outbreak, vaccination rates of around 94 per cent are required as measles is highly infective," Dr. Pauline Johnson told Alaska Highway News in an email.
Dr. Ninan Abraham, a UBC immunology researcher, said the Public Health Agency of Canada has a target coverage rate of 95 per cent for a given "herd."
"When you drop below 95 per cent, as in two of the school districts, the herd protection vanishes," he said. "[Measles] can actually find susceptible individuals, multiply in them and spread."
The differences in vaccination rates between northeast school districts is significant, according to the researchers.
"Especially one community (with the 85 per cent vaccination rate) would be more at risk than the 91 per cent and this more than the 97 per cent, which would be highly protected," Johnson wrote. "So there are increased risks for a measles outbreak in the community when the vaccination rate is 85 per cent, and, to a lesser extent even when it is 91 per cent."
While it is possible to compare rates in the districts, each had significantly different incoming class sizes last year.
SD 60 took in around 510 kindergartners, while SDs 59 and 81 had classes of 263 and 66, respectively.
That means increases or decreases in the number of children vaccinated will have larger impacts, either positive or negative, on the rate in the smaller school districts.
Children are typically given the first MMR vaccination at 12 months. Until recently, a booster was given at 18 months. That booster has since been pushed back until kindergarten, which has not impacted the drug's effectiveness.
The first shot is 85 to 95 per cent effective at preventing the disease, according to the BC Centre for Disease Control, while the kindergarten booster ups immunity to nearly 100 per cent.
Provincial law does not require that children entering public school have the vaccine. Districts are not in charge of distributing the shot, which is usually given by public health units.
Measles outbreaks in both the U.S. and Canada have thrust the vaccination issue into the headlines.
In 2014, a measles outbreak in the Fraser Valley infected several hundred people, according to the BC CDC, while an outbreak in Disneyland ahead of spring vacation has public health officials worried.
The Fraser Valley outbreak began last March at a religious elementary school and spread to the general public.
Vaccination rates in Peace River South are notably lower than in Fraser Health, where 86.6 per cent of kids had both measles shots in 2012 — the last year for which full provincial data is available.
According to Johnson, "the Fraser Valley outbreak illustrates what can happen when the vaccination rate is lower than 90 per cent."
"If I was a parent with a young child looking to go to school, I would consider this information when selecting a school," she wrote.
The provincial average for full MMR vaccination in 2012 was 88.6 per cent.