A pocket of unvaccinated children in northeast B.C. allowed cases of measles in the region to spread “like wildfire,” says B.C.’s deputy provincial health officer, Dr. Martin Lavoie.

He made the remarks during a provincial update on the disease that has seen multiple exposures reported in and around Fort St. John, including at an elementary school, emergency room and prenatal clinic.

“If the virus finds people who are not immunized, it will start infecting,” Lavoie said during the July 10 presentation given to media.

Over the past weeks, he added, “the virus has found communities or pockets of population that are large enough in numbers to allow the virus to all of a sudden, I would say, explode or start like a wildfire … and then it takes some time before it dies off and runs its course.”

The risks of allowing it to spread, he said, included serious disease or even death.

10 hospitalized, the majority infected children

According to provincial numbers, there is currently just one case of measles still active in the province. But as of July 8, 10 people were hospitalized due to the virus, with a total of 102 confirmed cases provincewide this year.

That’s the highest number in more than a decade, though still significantly less than a 2014 outbreak centred around B.C.’s Fraser Valley that resulted in 344 confirmed cases.

In that case, the epicentre of the disease was at a school where about 360 students from kindergarten to grade 12 were infected, according to the B.C. Centre for Disease Control.

Lavoie said the outbreak in northeast B.C. had followed a similar pattern, with the first case believed to be travel-related.

From there, an exposure was reported at an elementary school in the community of Wonowon, around 90 kilometres northwest of Fort St. John. Subsequent exposures were then reported at shops and businesses, as well as at Fort St. John’s emergency room and prenatal clinic for pregnant mothers.

The majority of those infected were under 18, provincial data shows, making up 70 per cent of known infections. The actual number is likely higher, Lavoie said, as many cases are known to go unreported.

Six of the 10 confirmed hospitalization cases in B.C. are located in Northern Health, with one in each of the four other health regions.

Lavoie said because the population of northeast B.C. is smaller than the Fraser Valley, he did not expect total infections to climb as high as they had in 2014, though he warned there was still a risk of travel-related infections bringing it to other locations.

He also noted that the virus was able to spread so successfully because it has been roughly 20 years since measles were in the region in any significant numbers, so there was an entire generation of unvaccinated people ready to be infected.

Northern Health’s chief medical health officer, Dr. Jong Kim, said the bulk of the infections had occurred in known “under-immunized, vulnerable communities,” but he hoped the peak of infection had already been seen, with cases now on the decline.

He also said outreach efforts were underway to communities in the region that are deemed to be most at risk of future outbreaks. According to the local school district, the school where the initial measles outbreak took place is 90 per cent Russian or German-speaking, in an area with religious communities who may not undergo regular vaccine schedules.

Lavoie said B.C.’s immunization rate of about 84 per cent was quite good but not perfect, while B.C. Health Minister Josie Osborne said getting immunized is the best thing B.C. residents can do to protect themselves and others.

Alberta experiencing highest per-capita measles rate in North America

B.C. released its latest case figures one day after Alberta had reported 1,230 infections since March.

While Ontario has reported the highest absolute number of cases with 2,244 confirmed infections since October, Alberta leads not only Canada, but also North America on a per-capita basis.

Lavoie said his office isn’t concerned that B.C. could be facing a similar situation.

WATCH | The risks of measles during pregnancy:

“So we are very close to Alberta, of course, so they could be a source [of measles] for us as people travel back and forth,” he said.

“We think our coverage rates are actually not in a bad place. I said they were good, not perfect, so I would doubt we would see something that big.”

Lavoie also acknowledged the high case count in Ontario and urged British Columbians to protect themselves.

Ontario reported last Thursday that an eighth infant had been born with congenital measles since the outbreak began last fall.

Infants can contract congenital measles in the womb through their mothers who are not vaccinated, resulting in severe complications, including inflammation of the brain and death.

The latest data in Ontario shows 48 pregnant people have been infected with measles, and Ontario’s chief medical officer, Dr. Kieran Moore, announced in early June that an infant born prematurely and infected with measles in southwestern Ontario had died.

Dr. Jennifer Vines, public health physician at the B.C. Centre for Disease Control, said during Thursday’s update that B.C. has not yet seen such a case.

“But we are preparing for it by engaging pregnancy experts to prepare for everything we need to know on how to manage measles in pregnancy … so we can be prepared for this unfortunate possibility,” Vines said.

Vines said the Ontario congenital cases reinforce the importance of everybody getting vaccinated, “but in particular, anyone who is pregnant, who knows they are susceptible to measles, getting quick follow-up if they think they have had a measles exposure, or seeking advice right away from their pregnancy provider.”

Lavoie said people who are pregnant and infants, including children less than 12 months old, are at risk of being infected with measles. Pregnant women and young children under the age of five also fall among the groups with a higher risk of complications and death.

Officials say those who have received two doses of the vaccine against measles should be fully protected, and that extends to babies born to vaccinated mothers, though infants should also follow recommended vaccine schedules.