Canada is reportedly on the verge of losing its “measles elimination” status due to an outbreak spreading from New Brunswick that began exactly one year ago on Monday.
Canada was certified by the World Health Organization (W.H.O.) as a nation that “eliminated” measles in 1998. Elimination status requires zero confirmed cases of local transmission for 12 consecutive months, although a modest number of cases imported by travelers from other countries are allowed.
For most of the past three decades, Canada has reported a median annual measles incidence of 0.87 cases per one million population. These vanishingly low numbers began to tick upward in October 2024 with the outbreak in New Brunswick, which appears to have begun with a single individual who contracted the disease at a large gathering of Mennonites.
Measles began spreading through Mennonite communities in Ontario, which tend to have low immunization rates due to their religious beliefs and cultural practices. Health officials also blamed the Wuhan coronavirus pandemic for disrupting routine measles, mumps, and rubella immunization schedules.
After one year of the measles outbreak, public health officials reported 2,375 cases in Ontario, plus 1,925 in Alberta. New Brunswick declared its outbreak was concluded in January and Public Health Ontario believes there have been no new cases outside the incubation period for measles, suggesting its outbreak could be formally concluded soon.
Canada’s incidence of measles infections is now roughly three times that of the United States. The U.S. reported 1,618 cases over the past year, but its population is 8.5 times the size of Canada. Mexico is also experiencing a substantial outbreak of measles, with case numbers roughly comparable to Canada.
According to Ontario officials, about 75 percent of the patients have been children and 96 percent of them were unvaccinated. Two infected babies reportedly died when their mothers gave birth prematurely, one in Ontario and the other in Alberta.
The Pan-American Health Organization (PAHO), the regional branch of W.H.O. for North and South America, is scheduled to meet in November to reconsider Canada’s measles elimination status. Revocation requires 12 consecutive months of local disease transmission, which clearly seems to have occurred in Ontario and Alberta.
The U.S. and Mexico will be up for a status review in January and February, respectively. The U.S. nearly lost its elimination status in 2019 after a major outbreak in New York but was able to avoid decertification. New York and South Carolina are both experiencing much smaller outbreaks at the moment.
