Alberta has the most measles cases in North America on a per-capita basis, worrying experts who say summer events could push case counts even higher.
Dr. Karla Gustafson, medical officer of health for the Calgary Zone of Alberta Health Services, said an influx of people visiting the province to hike the Rocky Mountains or watch the Calgary Stampede will give measles great opportunities to spread.
"Measles, of course, being very, very contagious, it's going to spread with travel and people moving about," Gustafson said Wednesday.
Alberta has twice the rate of confirmed measles cases as Ontario, where 1,910 confirmed infections have been reported since its outbreak began in October.
In absolute case numbers, Ontario is considered Canada's measles epicentre but its population is three times that of Alberta, Alberta's former chief medical officer of health noted Tuesday.
“We have a serious measles problem,” Dr. Mark Joffe said.
Alberta reported Wednesday that 1,246 people have been infected with the highly contagious disease since March.
In the United States, there have been 1,288 confirmed measles cases this year, according to the Centers for Disease Control and Prevention's latest data.
Dr. James Talbot, another former chief medical officer of health in Alberta, said the province has even outpaced India on a per-capita basis, which has approximately 10,000 measles cases, but a population of 1.4 billion.
Gustafson said it’s difficult to compare outbreaks in different countries. But regardless, she said “it's really disappointing that our Alberta numbers are so high.”
It comes as the province hosts more than one million people for its largest annual attraction, the Calgary Stampede, and just as summer camps, baseball tournaments and family camping trips create new potential opportunities for the virus to spread.
Talbot said it’s very possible that in two to four weeks a significant number of cases will be traced back to the Stampede, not just in Calgary, but in other parts of the province, country and abroad as visitors return home.
In May, Alberta’s government launched a measles immunization campaign, which it said has led to more than 75,000 shots administered across the province between March and June. They said that's an increase of more than 57 per cent compared to immunizations during the same period last year.
While Talbot said that’s good news, he said the government’s campaign should have launched months earlier, considering the outbreak began in March. He also noted a substantial portion of the population in Alberta is still unvaccinated.
Only 68 per cent of two-year-olds in Alberta were vaccinated with two doses of the measles, mumps, and rubella vaccine in 2024. In some jurisdictions, such as the town of Taber in southern Alberta, only 28.7 per cent of two-year-olds were fully immunized against the disease.
Herd immunity for measles requires at least 95 per cent of the population immunized.
While the summer is still in full swing, Talbot said he’s already thinking about the fall.
“What the government should really be doing now is pushing people to get their kids immunized before the school term starts,” he said, noting it takes 10 to 14 days to acquire full protection from the vaccine.
Gustafson said she's not aware of a specific media campaign targeting back-to-school measles immunization, but that it's routine for public health nurses to send personalized letters to parents of kindergarten and Grade 1 students who have fallen behind on shots.
She said those letters typically start going out at the end of the summer and beginning of the school year.
This report by The Canadian Press was first published July 9, 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
