Almost as many measles cases reported in Ontario this year as there were in all of 2023


Published March 12, 2024 at 4:59 pm

measles on the rise in ontario mississauga brampton peel

Since the start of the year, at least four individuals with confirmed cases of measles have spent time in a number of crowded places in Mississauga, including Pearson Airport, busy stores and a restaurant. 

But while measles is known as one of the most contagious viruses on earth and poses the risk of severe complications in some people, health experts are just urging residents–especially those who are travelling during March break–to ensure they’re up to date with vaccinations. 

It’s not COVID

Dr. Sumon Chakrabarti, an infectious disease physician at Trillium Health Partners in Mississauga, says that it’s important not to think of measles the same way we thought of COVID at the beginning of the 2020 pandemic. 

“I’m still getting the sense that people are looking at [measles] through the frame of COVID. I understand why, but if you go back, the idea of having multiple cases of measles come up in an outbreak, it has happened before,” he says. 

“We had a really bad outbreak in Canada in 2014. Yes, it’s there, and yes, it’s something for us to look at, but people are worrying about contact tracing and community transmission and it’s all COVID language.”  

While measles can be serious, it is, fortunately, vaccine-preventable–and the vaccine given to prevent it (the measles, mumps, rubella or MMR vaccine) is far from new. That said, Chakrabarti says that two doses are most effective and that some people born between 1970 and 1996 might only have received one dose as children and could benefit from a second shot.

Now, children are typically vaccinated at one year of age and again between the ages of four and six. 

According to Health Canada, the efficacy of a single dose given at 12 or 15 months is 85 to 95 per cent and with a second dose, efficacy is almost 100 per cent. 

“The vaccine is good for life,” explains Dr. Prasanna Selliah, the chief of pediatrics with the William Osler Health System.

“There hasn’t been much evolution or new variants of measles.” 

While measles remains relatively rare in Canada, the detection of new cases–most of them travel-acquired–has made headlines in recent months. Public Health Ontario reports that in 2024, six laboratory-confirmed cases of measles have been reported in the province. Five of the six cases have been linked to travel. 

In 2023, there were seven laboratory-confirmed cases of measles reported in Ontario, according to PHO.

Peel Public Health, which serves Mississauga, Brampton and Caledon, told that the region has seen one confirmed case of measles so far–same as last year.

“The Region of Peel typically has one reported measles case per year,” a PPH spokesperson said in an email.

Public Health Ontario says symptoms of measles include fever, a red blotchy rash, red, watery eyes, and cough. While most people who contract the illness can recover at home, severe complications are possible.

PPH says mild complications include ear infections, diarrhea, and pneumonia, and more serious complications include respiratory failure, encephalitis (brain inflammation that could result in hearing loss), pregnancy complications, and death. 

People most at risk of complications include children under five, those with compromised immune systems and unimmunized pregnant women. 

Why are cases rising?

As for why more outbreaks are being reported, health experts say there are a few factors at play. 

The World Health Organization (WHO) attributes the global rise in measles to fewer people being immunized amidst the crisis stage of the pandemic (2020 to 2022). PPH told that in Ontario, reported measles immunization rates among school-aged children are lower than pre-pandemic rates, but under-reporting should also be considered.  

“This is partly due to the lack of mandated reporting during the pandemic years among school-aged children. In some cases, children may have received the required vaccines, but their immunizations were never reported to Peel Public Health,” a spokesperson said in an email, adding that it’s the responsibility of parents and caregivers to report vaccines. 

“We have started to collect immunization information again this year and sending out communications to parents/guardians of children whose records are incomplete or not up to date. Suspensions under the Immunization of School Pupils Act (ISPA) have begun for some schools.” 

Other experts say that while vaccine disruptions and hesitancy play a role, increased travel–whether it is linked to leisure or global conflict–is also a factor. 

“During the pandemic, the immunization programs were interrupted and there’s still some vaccine hesitancy, but the vast majority of us have had one or two doses of vaccine. People born before 1970 have post-infection immunity, which is very solid for measles,” says Chakrabarti. 

“There’s a similar proportion of kids not vaccinated every year. Some groups are hesitant or resistant. One reason we’re seeing this around the world suddenly is that, during times of social unrest and war, we see this increase in vaccine-preventable illness. In times of war and conflict, people move around.” 

Chakrabarti says that when people move from one region with lower vaccination coverage to another, communicable diseases can spread in places they’re not typically found. 

“This problem is much bigger in Europe, where we’re seeing people coming from areas with less vaccine coverage. We do see cases happening in the community, but because so many people are immunized, the fire stops pretty quickly,” he says. 

The numbers in Europe bear out Chakrabarti’s observation. According to the WHO, over 30,000 measles cases were reported by 40 of the European Region’s 53 member states between January and October 2023. That’s a significant rise from the 941 cases reported in 2022. 

In a statement, the WHO’s regional director for Europe said the area has seen 21,000 measles-related hospitalizations and five deaths. 

While the global trend is alarming, Chakrabarti doesn’t believe an epidemic will take hold in Canada. 

“The idea of there being this massive epidemic or pandemic of measles stopping our lives, I don’t think that’s going to happen,” he says. 

What precautions are necessary? 

While Ontario has already reported six cases of measles, some health experts say they haven’t seen a significant increase in measles-positive patients. 

“I would say [we’re seeing] the same [amount of cases] as previous years because we don’t usually see much measles in the community. We are getting more questions about measles because there’s awareness in the community,” says Selliah. 

“There are some pockets of outbreaks and it’s a public health concern and they want to make sure that this is contained. The best practice is prevention, which is immunizations.”

Both Selliah and Chakrabarti agree that vaccination is the key to prevention and say that some infants and adults with just one dose might benefit from an early or additional shot before travelling. 

For example, an infant between six and 11 months of age could get an early dose and then complete the primary series upon returning to Canada at the recommended ages. 

PPH also says that children under four years of age who have received one MMR dose can receive their second dose before travelling internationally as long as the second dose comes at least 28 days after the first. 

“Current guidelines say that if your child is under one and travelling to a measles-endemic area, you can get a shot earlier and then come back to Canada and still get the primary series. If a child gets a vaccine at nine months, they should get the first shot at one and a booster between four and six years of age,” Selliah says. 

Adults might also want to consider a booster if they’ve only had one vaccine and plan to travel to a place where measles is more common.

“There are some people I would recommend a booster to,” says Chakrabarti, adding that measles outbreaks have been seen in the cohort of residents who only received one dose between 1970 and the mid-1990s. 

“You still have protection with one dose, but there’s a higher potential of a breakthrough infection. If you’re travelling, get that second dose if you don’t have it.” 

PPH also says that people born before 1970 can get an MMR shot before travelling.

“Those born before 1970 are generally considered immune due to measles circulation at that time. However, they are encouraged to get one dose of the measles vaccine if planning international travel,” the spokesperson says.

“There is a benefit to getting up to date with MMR any time before travel.” 

While the vaccine is very effective, additional or booster doses are not appropriate for everyone, especially those who are immunocompromised or pregnant. 

“MMR is a live vaccine, so you want to avoid it in someone who is profoundly immune-suppressed,” Chakrabarti says. 

He also says that if you know for sure you’ve had two doses, a third booster isn’t needed.

“If you’ve had two doses, no further doses are needed in most situations.” 

Dr. Selliah says other common sense infection prevention protocols apply.

“Vaccination is going to give you the best protection, but day-to-day [practices] such as handwashing, not touching your face after touching surfaces, etc. also help.” 

What to do if you–or your child–get the measles?

While cases still remain rare, un- or under-vaccinated people can still get sick. 

PPH says that anyone experiencing symptoms should stay home from school and work to prevent further spread and contact their doctor to discuss possible next steps. Those who suspect they have measles can also contact public health if they do not have a family doctor or their doctor is unavailable. 

“Management of measles is symptom-based. If symptoms are mild, they can be managed at home,” says Dr. Selliah.

“If your child should develop concerning symptoms, they might need to seek care in person, including at the emergency room. More serious symptoms include dehydration, a persistent cough that might require an assessment or a change in neurological function. If a child is very lethargic, families should seek care in the emergency room.” 

Selliah says that if a child has a confirmed or suspected case of measles and requires medical care, the parent should let staff know immediately. 

“If there are more serious symptoms, go to your nearest emergency room and notify triage nurses when you arrive that there’s concern for measles and wear a mask,” she says. 

PPH says that even fully vaccinated people should monitor for symptoms in the event they’re exposed to measles. 

“Two doses of measles-containing vaccine is over 95 per cent effective at preventing measles. Even individuals who are up to date with the measles vaccine should watch for signs or symptoms of measles if they are exposed to a measles case,” a spokesperson told 

How worried should people be?

With most cases of measles still coming from abroad, some residents might be wondering if they should pare down or restrict travel.

Chakrabarti says that probably isn’t necessary.

“This is another thing that’s a hangover from COVID. Right now, there are certainly places where there is an increased risk of measles, but will we tell people not to go there? We don’t tell people not to go to Canada due to flu season. If a child is over six months old, get them a shot. If you’re an adult, you can consult a travel clinic where you can talk about MMR.”

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