Canada Could Lose Measles Elimination Status if Outbreak Lingers Past Mid-October, Health Official Warns

On Thursday, Public Health Ontario added 197 measles infections to its weekly count, bringing the province's total of probable and confirmed cases to 1,440 since the outbreak began in October. Within hours, a senior federal health official was telling reporters that the country's standing as a place where measles has been eliminated is now in question.

Dr. Marina Salvadori, a senior medical advisor with the Public Health Agency of Canada, said Canada could lose its elimination status if the disease keeps spreading past mid-October 2025. Elimination means no continuous transmission of the disease for 12 months or more in a given area. Canada reached that mark in 1998.

Salvadori was careful about what losing the status would and would not mean. She said that when people hear the phrase, many fear measles will take root again and become common, exposing everyone for decades. In her view, that does not have to follow. Even if the status lapses, she said, she believes Canada can eliminate measles again.

The outbreak is not confined to one country. Salvadori said Canadian officials have been meeting with the U.S. Centers for Disease Control and Prevention and with public health colleagues in Mexico, because the outbreak has struck all three. She described the effort as a shared one, with the countries working well together to gain insight into what is happening.

In Ontario, the toll is measured in hospital beds. There have been 101 hospitalizations, 75 of them children, and eight patients have required 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. She called that a clear sign that measles can cause severe complications and is not a trivial infection.

Other provinces reported their own numbers. Alberta's count has reached 313 cases since mid-March, including 19 hospitalizations. Saskatchewan updated its cumulative total to 27, and Chief Medical Health Officer Dr. Saqib Shahab said he expects new cases every day going forward. Manitoba reported 24 cases on Wednesday. Nova Scotia and the Northwest Territories each reported measles cases earlier in the week, their first since this outbreak began.

Speaking at a news conference in Regina, Shahab said Saskatchewan is now part of what he called an unprecedented North American measles outbreak. He said measles should not be seen in 2025, and that outbreaks in specific communities that resemble the 1950s mean the social contract of keeping each other safe and protected is broken.

The mid-October threshold is the date to watch. If transmission is still continuing then, Canada's elimination status is at risk. Health officials say that would not be the end of the matter, since they believe it can be won back.