There's been another sharp increase in Ontario measles cases as the province begins to release weekly reports on the infectious disease.
Public Health Ontario is reporting 470 measles cases since an outbreak began in October. That’s an increase of 120 cases since March 14.
The spread resulted in 34 hospitalizations, including two people who needed intensive care. Most of those hospitalized were unvaccinated kids, including one of the intensive care patients.
The outbreak expansion adds to the growing concern of rising measles cases in different parts of the country, including in Quebec where there are 40 cases and Alberta where there are 13, according to the latest data.
Dr. Sarah Wilson, a public health physician at Public Health Ontario, said reining in the spread won't happen overnight, and that the challenge of boosting immunization efforts falls on the shoulders of local public health units.
"I don't expect that this current outbreak is going to continue indefinitely. I think that vaccination will be the way which we control the outbreak," Wilson said.
That also includes debunking misleading information about measles. Dr. Ninh Tran, medical officer of health at Southwestern Public Health, addressed one of these misconceptions at a media briefing Thursday, addressing the idea that getting infected with measles will result in immunity.
"While getting measles can result in natural immunity, carrying measles can result in significant health risks, including pneumonia, brain infections and brain swelling," Tran said.
He also highlighted the potential for long lasting neurological problems measles can cause.
The majority of cases are still located in the Southwestern Public Health region, where almost half of the cases are reported, and neighbouring Grand Erie, which has almost 24 per cent.
Nine per cent of the province’s cases are now in Huron Perth, a region that includes Stratford and Goderich, rising from 3.7 per cent last week. Local public health officials have deemed it an area of concern.
As a resident of Listowel in Huron Perth, Andrea Charest said a hyper local approach is needed in the community. Charest, co-founder and executive director for social organization It Takes a Village, said that means ensuring people have transportation to reach a clinic, and awareness of where those clinics are.
"I also think that we need to be sure that we're showing kindness and support to folks if their vaccination is not up to date because I think sometimes too, there's that element of shame and embarrassment ... we have to have care and compassion when we're navigating these situations with people. Otherwise people are not going to be able to come forward comfortably and say, 'I need some help with this,'" she said.
In Quebec, an outbreak began in December with most cases reported in Laurentides region, well-known for skiing. Hockey fans who went to a Montreal Canadiens game earlier this month are still being asked to monitor for symptoms.
In Alberta, most cases are in the province's north, but measles also reached the southern area of Taber this week after a traveller coming from Toronto visited several spots while infectious.
Ontario now puts out a weekly report after previously publishing case numbers biweekly, while Alberta has started releasing data daily from Monday to Friday.
Wilson said the move to weekly reporting was done to reflect the fact that case counts are "changing quite frequently," given that measles is one of the most contagious diseases in the world. The World Health Organization says the virus can remain active in the air or on infected surfaces for up to two hours.
It 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 March 20, 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
