As Canada’s measles outbreak continues to grow, the country is at risk of losing its measles elimination status — a bar set by the World Health Organization.

“The risk is substantial,” said Dr. Sarah Wilson, a public health physician with Public Health Ontario who has been tracking the measles outbreak in that province.

Ontario is now reporting more measles cases each week than it once saw over an entire decade, Wilson said. “It is a very different situation than what we experienced in the last decade since measles elimination was achieved,” she said.

Canada’s outbreak began in October 2024. That means if sustained transmission continues until October 2025, the Pan American Health Organization (PAHO) can revoke the elimination status.

Canada currently has more cases than any other country in the Americas, according to PAHO.