Measles is making an international comeback. Should Canadians be concerned?

The World Health Organization (WHO) as well as the U.S. Centre for Disease Control (CDC) have issued warnings regarding the resurgence of measles in Europe and the United States. So the question is, should Canadians be concerned?

With a recent warning from the Windsor-Essex health unit about possible exposure at a local clinic in that region in January, Dr. Isaac Bogoch says we have to be prepared.

“This is one of those infections where we have to have vigilance to maintain those very high vaccine rates because there’s not a lot of wiggle room with measles. It’s extremely transmissible. And if your vaccine rates get a bit lower, you’ll start to see explosive outbreaks,” says the infectious disease specialist.

Even with vaccination rates against measles above 90 per cent in most of Canada, there are weak links in the country’s defense against the disease that Bogoch says need to be shored up.

He says one growing concern is declining vaccination rates over the recent past.

“We’ve seen over the last few years a lot of polarization. A lot of disinformation … we really need to build back public trust in public health.”

“Unfortunately we’re in an era where more and more people are choosing not to vaccinate themselves or their children. This is a huge problem. And if we see that persist, we’re going to see outbreaks of vaccine-preventable illnesses.”

He says people should not get complacent about measles vaccinations simply because it is no longer an imminent threat in the country. It also shouldn’t be taken lightly, as it can be a dangerous infection.

“The first thing is that if people get a measles infection, they’re more prone to other infections like bacterial infections. In fact, pneumonia is a very serious and common complication after measles. The second thing is the virus itself can cause inflammation of the brain, which can be very, very dangerous. The third thing is that measles wipes out preexisting immunity to other infections. So you’re almost immunocompromised to some extent, after a measles infection. So you may have been vaccinated against other pathogens, but if you get a measles infection, it can dampen down that vaccine.”

Bogoch adds that the measles, mumps, and rubella vaccine (MMR) is extremely safe and effective and is widely available for free in Canada. However he notes that other countries might not have equally widespread measles immunization programs, so newcomers to Canada should be mindful of their vaccination status.

“There’s so many people who have moved to Canada from other parts of the world where perhaps the public health systems aren’t as robust. Some of those people might already be immune to measles because they’ve had an infection in the past, but some of them might not have been. And it’s really important that all Canadians, especially new Canadians, are up to date on their vaccines,” he says.

Another factor that could possibly be of concern for herd immunity levels is that those who were vaccinated before 1996 might not be fully protected.

“It’s important to note that in 1996, a second dose of the measles vaccine was added. There were lots of catchup campaigns to ensure that people had the two doses of vaccine, but there are still some people that might have one dose of a measles vaccine. They might think they’re fully vaccinated, but they’re not, and some of those people might be susceptible to measles.”

For children, the first dose of the vaccine is given at 12 months and the second around 18 months. No further boosters are required.

Bogoch says your family physician can run a simple blood test to check if you’re immune to measles and if not, he advises you to take the two-shot series as soon as possible.

“If people get two doses of the vaccine, the protection is probably north of 97 per cent,” he says.

But despite high vaccination rates, Bogoch says it is inevitable that Canada will see measles cases as international rates rise.

“There’s a guarantee that we’re going to import measles. There’s lots of cases of measles all over the world. We live in an era with unparalleled human mobility … and certainly, we’ve seen imported cases of measles in Canada in the past years … it’s going to happen. The key thing here is we can control what happens in our country … we can ensure that Canadians have easy access to measles vaccines and other vaccine-preventable illnesses … we have such high levels of vaccination and we should keep it that way,” he says.

“Obviously, this is a completely preventable disease. We should not have any infections in Canada, apart from imported infections on occasion. But if we do import an infection, we shouldn’t see any onward transmission within the country because our vaccine rates should be above 95 per cent.”