In the spring of 2025, a measles outbreak that began in Ontario in October has grown into a North American concern, and Canada now faces the possibility of losing a hard-won public health achievement it has held since 1998. Officials say the question turns on time: if transmission keeps moving past mid-October, the country's elimination status would be in doubt. Across the provinces, families and clinicians are living with the cost of a disease many believed had been left behind, and the reminder that protection depends on a shared, ongoing agreement to look after one another.
Canada Could Lose Measles Elimination Status if Spread Persists Into Fall, Federal Advisor Warns
101 Ontario measles hospitalizations, including 75 children, and eight patients in intensive care.
"We should not be seeing measles in 2025."
Mark
Why does the mid-October date matter so much?
Mimi
Elimination means 12 months without continuous transmission. The outbreak began in October, so if spread continues beyond mid-October 2025, that threshold is crossed.
Luke
Worth being precise: Salvadori said it "could" happen. That's a conditional, not a forecast.
Mark
She also seemed keen to soften what losing the status means.
Mimi
Yes. She said people fear measles becoming common again for decades, but loss doesn't have to mean that, and she believes Canada could eliminate it again.
Luke
That's her view of the outcome. The reporting doesn't give a timeline or mechanism for regaining status.
Mark
The hospitalization numbers are stark.
Mimi
101 in Ontario, 75 of them children, eight in intensive care. Dr. Wilson pointed out that's seven per cent of cases.
Luke
Those are Ontario figures from probable and confirmed cases. We shouldn't carry that seven per cent over to Alberta or elsewhere.
Mark
And the cross-border piece?
Mimi
Officials are meeting with the US CDC and Mexican colleagues, since all three countries face the outbreak.
Luke
The story says they're sharing insights. It doesn't say what they've found or whether any joint action is planned.
Le Pouls
- Ontario's measles count jumped by 197 in a single week, bringing the outbreak to 1,440 cases since October.
- A senior federal advisor warned that Canada could lose its measles elimination status if spread continues past mid-October 2025.
- Ontario has 101 hospitalizations, 75 of them children, and eight patients are in intensive care.
- Alberta, Saskatchewan and Manitoba are reporting rising cases, and officials expect new infections daily.
- Health authorities in Canada, the United States and Mexico are coordinating closely to understand and contain the shared outbreak.
In the spring of 2025, a measles outbreak that began in Ontario in October has grown into a North American concern, and Canada now faces the possibility of losing a hard-won public health achievement it has held since 1998. Officials say the question turns on time: if transmission keeps moving past mid-October, the country's elimination status would be in doubt. Across the provinces, families and clinicians are living with the cost of a disease many believed had been left behind, and the reminder that protection depends on a shared, ongoing agreement to look after one another.
On Thursday, Public Health Ontario added 197 measles infections to its weekly count, bringing the province's total to 1,440 since the outbreak began in October. The same day, a senior medical advisor with the Public Health Agency of Canada warned that the country could lose its measles elimination status if the disease keeps spreading into the fall.
The advisor, Dr. Marina Salvadori, named a specific deadline. Elimination means no continuous transmission for 12 months or more, and Canada earned that status in 1998. Losing it would require prolonged spread beyond mid-October 2025. She stressed that losing the status does not mean measles must become permanent, and she believes Canada can eliminate it again.
The outbreak crosses borders, and officials in Canada are working with the US Centers for Disease Control and Prevention and with Mexican colleagues to share insights.
In Ontario, 101 people have been hospitalized, 75 of them children, and eight are in intensive care. Dr. Sarah Wilson of Public Health Ontario said the hospitalization rate is a clear sign that measles is far from a trivial infection. Elsewhere, Alberta has reached 313 cases, Saskatchewan's health officer expects new cases every day, and Manitoba, Nova Scotia and the Northwest Territories are also reporting infections. What happens by mid-October will decide whether Canada keeps its status.
On Thursday, Public Health Ontario added 197 measles infections to its weekly count, pushing the province's total of probable and confirmed cases to 1,440 since the outbreak began in October. On the same day, a senior medical advisor with the Public Health Agency of Canada said the country could lose its measles elimination status if the disease keeps spreading into the fall.
The advisor, Dr. Marina Salvadori, put a date on the risk. Losing the status would happen only if prolonged spread continued beyond mid-October 2025. Elimination means no continuous transmission of the disease for 12 months or more in a geographic area, and Canada achieved it in 1998.
Salvadori was careful about what a loss would mean. She said that when people hear the phrase, they fear measles will re-establish itself and become common, exposing everyone over the coming decades. It does not have to mean measles is here to stay, she said, and even if the status ends, she believes Canada can eliminate the disease again.
The outbreak is not confined to Canada. Salvadori said public health officials have been meeting with the United States' Centers for Disease Control and Prevention and with colleagues in Mexico, because all three countries are dealing with the same outbreak. They are working well together, she said, to gain insights and understand what is happening.
In Ontario, the outbreak has brought 101 hospitalizations, 75 of them children, and eight patients have been in intensive care. Dr. Sarah Wilson, a public health physician at Public Health Ontario, noted that hospitalizations make up seven per cent of the province's outbreak cases. To her, she said, that is a clear sign that measles can cause very severe complications and is absolutely not a trivial infection.
Other provinces reported their own numbers. Alberta said its overall count had reached 313 cases since mid-March, including 19 hospitalizations. Saskatchewan updated its cumulative total to 27, and Manitoba reported 24 cases on Wednesday. Nova Scotia and the Northwest Territories each reported measles cases earlier this week, their first since this outbreak began.
Saskatchewan's Chief Medical Health Officer, Dr. Saqib Shahab, said at a news conference in Regina that he expects new cases every day going forward. He said Saskatchewan is now part of an unprecedented North American measles outbreak. Measles should not be showing up in 2025, he said, and outbreaks in specific communities that look like the 1950s mean the social contract of keeping each other safe and protected is broken.
What to watch is whether transmission is still going when mid-October arrives. That is the point past which Canada's elimination status, held since 1998, would be in question.
Citations marquantes
Even if elimination status ends, I do believe we can eliminate measles again in our country.— Dr. Marina Salvadori, Public Health Agency of Canada
Measles infections can have very severe complications and it absolutely is not a trivial infection.— Dr. Sarah Wilson, Public Health Ontario
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