Ontario measles case count exceeds 800 total infections, 155 new since last week

A sign outside Southwestern Public Health in St. Thomas, Ont. on Tuesday, March 4, 2025 warns residents to call ahead before visiting a doctor or hospital if they think they have the measles. THE CANADIAN PRESS/ Geoff Robins

TORONTO — Ontario is reporting 155 new measles cases over the last week, pushing the province’s case count to 816 since an outbreak began in the fall.

The number of new cases has increased again after a few weeks of appearing to stabilize in the 100-per-week range, which public health physicians had taken as a sign of potential optimism.

Dr. Sarah Wilson, public health physician at Public Health Ontario, says the fact that Ontario has exceeded 800 cases is striking.

"It’s precedent-setting in terms of its size," Wilson says, reflecting on the magnitude of the spread.

She says it speaks to the fact that the outbreak is going to take time to get under control as it continues to circulate in pockets of unvaccinated communities.

"This is not going to happen in days or weeks," Wilson says.

Public Health Ontario says there have now been 61 hospitalizations – that’s 11 more than last week – including three in intensive care. Unimmunized kids are the predominant group infected by the outbreak, with 47 minors hospitalized.

Most cases are still in Ontario's southwestern public health unit, and spread to two more public health units this week, including Hamilton and Northeastern, which covers Timmins and Englehart.

Southwestern's Dr. Ninh Tran says there’s been a 130 per cent increase in measles vaccinations at local public health clinics from January to April compared to last year.

That translates to an additional 940 doses in arms.

Tran also spoke about schools beginning to issue suspensions this week to some of the thousands of students who aren't fully vaccinated, and the urgent calls for the province to digitize its immunization record system.

Physicians have been calling on the province to create a central digital vaccine registry for over a decade with the spread of measles shining light on the outdated yellow immunization cards.

Tran says an electronic vaccine registry would be "absolutely critical" to better understand vaccine coverage.

"People can't seem to find them," he says about paper-based vaccine records. "They have to sort of contact their health-care provider and then report it to us."

Dr. Milena Forte, Toronto family physician, says kids have been coming into her office with suspension notices and that often they are in fact vaccinated — they just haven't presented the school with proof.

Reaching those who actually are unvaccinated is a task family physicians are well-versed at, but she worries about those who don’t have a health provider to openly discuss their vaccination concerns with.

“I don't try and convince anyone to get vaccinated, but I present information to them and I ask about their concerns … And I just say, I want you to know what I know. And here's the information I can share with you,” Forte says.

“It's credible information because I think they trust that I have a certain degree of expertise, but it's also credible because they know I know them and I'm trying to look out for what's in their best interest and their family's best interest.”

Alberta’s case count nearly doubled over the last week to 46, as did Saskatchewan's now six infections. Quebec has remained at 40 for a fourth week.

Manitoba has reported 10 cases since February, including an exposure on a flight from Toronto to Winnipeg, according to the latest update Monday.

Measles usually begins with a fever, cough, runny nose and red watery eyes, followed by a red blotchy rash that starts on the face and spreads to the body and limbs.

The virus can lead to pneumonia, inflammation of the brain and death.

This report by The Canadian Press was first published April 10, 2025.

Canadian Press health coverage receives support through a partnership with the Canadian Medical Association. CP is solely responsible for this content.

Hannah Alberga, The Canadian Press