A measles outbreak in New Brunswick is set to push Canada’s annual case count to the highest it’s been in five years, highlighting how infectious the disease is and how low vaccination rates have allowed it to take hold, says an immunologist.
There are 43 cases in the province, as of Friday, all in health Zone 3, which includes Fredericton and parts of the Upper Saint John River Valley area, according to the Department of Health.
That’s a 72 per cent increase in the three weeks since Public Health reported the initial case Oct. 24, involving a person who recently travelled internationally.
All of the cases can be traced back to that one, said department spokesperson David Kelly.
Thirty-six of them — or nearly 84 per cent — are 19 years old or under, he said.
The New Brunswick outbreak, declared on Nov. 1, is part of a national surge, which reached 100 cases as of Nov. 2, and resulted in the death of child under five in Hamilton, according to the Public Health Agency of Canada.
The last time the country saw more cases was in 2019, when 103 cases were confirmed.
New Brunswick is doing the heavy lifting, which is “unusual in some ways because often we’ve seen measles outbreaks in large urban centres,” said Dawn Bowdish, an immunologist and professor of medicine at McMaster University in Hamilton.
“But this just speaks to the fact that measles, once it gets into a population, can spread really, really quickly, and we have more vulnerable children than we’ve had in decades in Canada,” she said.
Measles is the most infectious respiratory infection experts know of, said Bowdish, citing an investigation that found when an infected child got off a plane at an airport, an unvaccinated person three gates down got sick. “So that’s just how contagious it is.”
The virus is transmitted through the air or by direct contact with nasal or throat secretions of an infected person.
It can also take eight to 12 days for symptoms to appear, so people can be contagious without knowing it and easily spread the virus to others. Symptoms of the measles may include fever, cough, sore and/or red eyes, runny nose or tiny white spots in the mouth. A red blotchy rash will subsequently appear, first on the face and then spreading to the body, arms and legs.
Vaccination rates below target
Meanwhile, vaccination rates have fallen around the world because many countries have “either lost faith in vaccines or lost the political will to get people vaccinated,” she said, which increases the likelihood of travellers bringing the virus back.
That’s compounded by the fact the COVID-19 pandemic interrupted routine childhood vaccinations in Canada in 2020-21, said Bowdish, and the current lack of access to family doctors, which she described as being a “major driver” in low vaccination rates among children.
According to New Brunswick’s 2023-24 school immunization report, among kindergarten students with proof of vaccination, 91.2 per cent have the required two doses of the measles, mumps and rubella, or MMR, vaccine.
That’s down from 91.4 per cent in 2022-23 and below the national target of 95 per cent by 2025 to provide so-called herd immunity, where there’s enough community resistance to a disease that it’s unlikely to spread.
Outbreaks can help boost vaccination rates, said Bowdish, pointing to a “collective forgetfulness, where we don’t remember just how bad measles is.”
“It actually kills your immune cells” and can lead to other complications, she said, so children who get measles often get other infections and need other antibiotics or treatments afterward.
Measles can cause ear infections or pneumonia and can sometimes lead to swelling of the brain, which can cause seizures, deafness, brain damage or even death.
Vaccination is the best defence, said Bowdish.
Horizon Health Network has been holding a number of vaccination clinics in Zone 3. Upcoming clinics include:
- Fredericton Public Health office, 300 St. Mary’s St., on Nov. 22, from 9 a.m. to 11:45 a.m. and from 1:15 p.m. to 3:30 p.m.
- Stanley Health Centre, 69 Limekiln Rd., on Nov. 29, from 10 a.m. to noon and from 1 p.m. to 3 p.m.
Primary care providers and Public Health offices can also offer the vaccine to eligible New Brunswickers.
“The measles vaccine is considered very effective at preventing infection, is safe, and has been in use for more than 50 years,” Kelly said.
People who are unsure of their vaccination status, or that of their children, are urged to contact their health-care provider or local Public Health office, he added.