Canada has lost its measles elimination status after nearly three decades due to its failure to curb a year-long outbreak, the country's public health agency has said.
Canada was formally declared measles-free in 1998, an achievement credited to years of consistently high childhood vaccination rates.
But an outbreak that began in the eastern part of the country in October 2024 has spread nationwide, notably among certain groups of Mennonite Christians who have refused to vaccinate their children on religious grounds.
Canada has so far recorded 5,138 measles cases in 2025, with Ontario and Alberta provinces the hardest hit.
Two newborns, born to unvaccinated mothers, have died from the virus.
Health Canada, a government agency, said in a statement that the Pan American Health Organization (PAHO) notified it that the country had lost its elimination status.
The update came after PAHO confirmed "sustained transmission of the same measles virus strain in Canada for a period of more than one year."
It said that, in response, provincial health ministers were "discussing coordinated actions, including strategies to build trust (in vaccines) through community engagement."
Health Canada noted that while measles "transmission has slowed recently," the outbreak has persisted "primarily within under-vaccinated communities."
The disease is a highly contagious respiratory virus spread through droplets when an infected person coughs, sneezes, or simply breathes.
It causes fever, respiratory symptoms and a rash, but can also lead to serious complications, including pneumonia, brain inflammation and death.
Step backwards in time
"Loss of elimination status is a step backward and a return to more primitive times, where voices from the Dark Agescontinue to attempt pull us," said Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security.
A spokesperson for the province of Alberta, one of the worst-affected Canadian provinces, said cases are down more than 90% from the peak with only two active cases in Alberta for the past several weeks. It said vaccinations since March are 50% higher than a year earlier.
To be considered measles-free, a country must stop the spread of the virus and be free of locally transmitted cases of the same strain for 12 months or greater, in addition to having high-quality surveillance systems.
The United States and Mexico have had significant measles outbreaks this year, with thousands of cases and a handful of deaths. Other wealthy countries, including those in Europe, have also been facing declining measles vaccination rates.
The Americas region only regained its measles-free status in 2024, after an outbreak in Brazil was stopped.
To retain its elimination status, the United States has a deadline of 20 January to prove it has halted continuous transmission of the strain that started in Texas on 20 January last that kicked off a large outbreak, according to Dr Demetre Daskalakis, a former US Centers for Disease Control and Prevention immunisation official.
The US will also need to prove that ongoing cases are not related to the Texas outbreak. Investigations are underway to determine that, he said.
Measles vaccination rates in the US among kindergartners have been on the decline, government data shows.
The office of Canada's Health Minister Marjorie Michel declined to comment.
Manitoba and Ontario, two of the hardest-hit Canadian provinces, did not immediately respond to requests for comment.
