How health units in northwestern Ontario are preparing for the potential spread of measles
No cases have been confirmed in the region in 2025 so far

As cases rise across the country, public health officials in northwestern Ontario are closely watching the spread of measles in the province.
On Thursday afternoon, the Northwestern Health Unit (NWHU) issued an alert about a risk of measles exposure at Toronto Pearson Airport on March 2 at Terminal 1, between 4:50 p.m. and 7:40 p.m.
"Anyone who was at the following location between the times listed is considered exposed to measles," the NWHU said.
People are urged to monitor for symptoms until March 23.
Measles is a highly contagious airborne respiratory infection that can cause fever, a red blotchy rash, red watery eyes, and a cough, according to Public Health Ontario.
Up until last week, cases of the previously eradicated disease had not been detected in northern areas of the province. However, the North Bay Parry Sound Health Unit reported a case on March 7, marking the first confirmed case in the region since 1995.
"We're keeping abreast of all of the information that's coming our way, understanding that we don't have any cases here in Thunder Bay yet and hopefully we're going to keep it that way," said Karen Battigelli, manager of the infectious disease program at the Thunder Bay District Health Unit (TBDHU).
"We know isolation processes. We know periods of communicability. We would definitely activate our measles response, should we identify even one case of measles," she said.
Oftentimes, northern Ontario lags a few weeks behind the south when it comes to the spread of infections and outbreaks. Battigelli says this "does give us the advantage of seeing what's happening within the province to get ourselves positioned in order to deal with a situation, should it come our way."
Ontario's Chief Medical Officer of Health issued a statement Friday morning, indicating the province has seen 350 cases of measles since 2024, including 31 hospitalizations.
Nearly half of those cases have been confirmed in recent weeks.
"This is the most measles cases Ontario has seen in over a decade. It is critical we work together to mitigate further spread of this vaccine-preventable disease," said Dr. Kieran Moore, Ontario's chief medical officer of health.
Public Health Ontario said 96 per cent of cases in Ontario are among individuals who are unimmunized, or have unknown immunization status, and were exposed in their community or while travelling. A majority of Ontario's cases are concentrated in southwestern Ontario among unvaccinated people.
Who should get vaccinated?
As March break draws to a close, the risk of transmission is high as airports across the world prepare for an onslaught of traffic, said Donna Stanley, director of health protection at the NWHU.
She says the health unit's catchment area has about a 90 per cent immunization rate for measles. However, the ideal situation is to have 95 per cent coverage in a population "to know that you're unlikely to have sustained spread."
Similarly to the TBDHU, "we're actually in the process of assessing the kids in the schools and working on catching up [on] some immunization that way," Stanley said.
If you have received two doses of the measles, mumps and rubella (MMR) or measles, mumps, rubella and varicella (MMVR) vaccine, health officials say you are highly protected. The federal government estimates one dose is 85 to 95 per cent effective, while two doses provide near 100 per cent protection.
In Ontario, children are expected to receive the first vaccine dose at 12 months and then a second dose between four and six years old. To check your or your kids' vaccination status, people can consult with their family doctor, vaccination record or provincial immunization portal.
If you were born before 1970, Health Canada considers you immune, because it's likely you contracted the virus at some point in time — though you should still speak with a family doctor to ensure you don't need the vaccine.
According to Stanley, people who plan to travel internationally, attend post-secondary school or work in health care should consider a booster dose.
While it can be more challenging in the north to raise vaccination rates, given the amount of travel required for health-care staff to get to smaller communities, Stanley said the NWHU is well-equipped to manage an outbreak if one occurs.
Regardless, she encourages everyone to stay on top of their immunizations to keep themselves and their loved ones safe.
"I know it's really challenging for people. I think people don't want to be told what to do," she said. "But this really is the best tool. It's a way to protect yourselves and family so that you can enjoy life and enjoy travel without fear."
The Government of Canada provides weekly measles and rubella monitoring reports online.