Alberta measles cases rise again after weeks of decline

Alberta's measles outbreak is showing signs of making a comeback, with the province confirming 27 new infections since this past Friday.

Alberta’s measles outbreak is showing signs of renewed transmission after weeks of declining case counts, with 27 new cases reported since last Friday according to provincial data.

Five new cases were identified Tuesday, bringing the total number of confirmed measles cases since March 2025 to 2,041 as of Jan. 15.

Provincial figures also show 164 people have been hospitalized due to measles during the outbreak, including 15 intensive care admissions but no patients currently remain in hospital.

While transmission had slowed significantly through late fall and early winter, infectious disease specialists say the recent increase shows the virus continues to circulate.

“We’re not out of it yet,” said Craig Jenne, a professor in the Department of Microbiology, Immunology and Infectious Diseases at the University of Calgary.

“This is a pretty clear reminder that measles is out there, and it does continue to spread. The good news is we’re not seeing broad community spread. These seem to be smaller clusters, but the virus is here.”

Uptick follows months of lower case counts

For much of the past two months, Alberta’s daily measles numbers had remained relatively low before rising again late last week.

“We had seen low numbers of cases over the last two months,” said Dr. Karina Top, a professor of pediatrics at the University of Alberta and a pediatric infectious disease specialist at the Stollery Children’s Hospital in Edmonton.

“Since November, we’ve generally had less than 10 cases a week, but that seems to have changed since late last week. We haven’t seen numbers that high since about mid-August.”

Top said new infections are now being detected in more than one region of the province.

“We’re seeing new cases in both North Central and South Zone,” she said.

“So it suggests that there’s quite a bit of transmission, with multiple areas of transmission across the province.”

Provincial data shows the South Zone continues to account for the largest share of cases, with 1,028 confirmed infections since the outbreak began, while the North Zone has recorded 773 cases.

As of Jan. 15, Alberta had 15 known active cases.

In a statement, the Ministry of Primary and Preventative Health Services said most of the recent cases are linked to household transmission rather than broader community spread.

“Most new cases reflect transmission within a small number of families, likely linked to holiday gatherings, rather than widespread community transmission,” the ministry said.

Vaccination gaps leave province vulnerable

Experts say the renewed increase reflects ongoing gaps in measles immunization coverage across Alberta.

“One reason why we still have measles in the province is the vaccine rate still has not climbed high enough to get to herd immunity,” Jenne said.

“So when measles enters a province, either through travel or other ways, it has people who it can infect.”

Jenne said low-level transmission can also continue as long as a sufficient number of people remain unprotected.

“There are enough people in the province who are not immune to measles,” he said.

He warned the situation could escalate if measles spreads within under-vaccinated communities.

“What we’re watching for and what we’re a little bit worried about is when we reintroduce measles into an under-vaccinated community,” Jenne said.

“We know there are a number of pockets in Alberta that are significantly under-vaccinated.”

Top echoed those concerns, noting the latest increase raises the possibility of another surge.

“And that can always lead to complications, hospitalizations, and put even more strain on our healthcare system.”

“Measles is a serious disease and it’s not just a common viral illness.”

Provincial data shows about eight per cent of people infected in Alberta have required hospitalization, with most admissions involving children.

“Almost the large majority of those hospitalizations have been in children,” Top said.

She added that complications can include ear infections and pneumonia, and in rare cases, brain inflammation.

“That can be fatal or lead to permanent brain damage and measles can weaken the immune system long after the initial infection.”

Top says that immune suppression can increase the risk of severe infections months after recovery.

“We’re actually seeing cases of that across the country with children admitted months after having measles with severe pneumonia and severe viral infections.”

Added pressure on hospitals

The renewed transmission comes as Alberta hospitals continue to manage high volumes of influenza, RSV and COVID-19 cases.

“If we go back five years ago before COVID, we were largely dealing with influenza and some RSV,” Jenne said.

“Now five years later, we’re dealing with influenza, RSV, COVID, as well as potentially measles cases.”

Jenne said the health-care system has little flexibility.

“This is turning out to be a record year for flu cases so there’s not much room to begin with in the hospitals.”

Top says measles cases can create outsized pressure because patients must be placed in airborne isolation.

“We have a limited number of those types of rooms in any health facility,” she said.

“When people walk into a health facility with measles, even if they’re only in a waiting room for five or 10 minutes, they can expose everyone in that waiting room and that leads to huge efforts in public health and in the hospital to identify all the people who were exposed.”

Province points to immunization efforts

The Alberta government says vaccination remains the primary tool to limit further spread.

“Public health officials continue to implement targeted vaccination campaigns, expand clinic hours, and conduct provincewide outreach to increase immunization uptake and limit further spread,” the ministry said.

The province’s “Don’t Get Measles, Get Immunized” campaign launched in May and has been extended through the end of March, featuring advertising in more than 14 languages.

More than 162,000 measles vaccines were administered between March 16 and Jan. 3, according to provincial data — a 39 per cent increase compared with the same period last year.

“In the South and North Zones, where historical uptake has been lower, vaccinations rose by 72 per cent and 65 per cent, respectively,” the ministry said.

The province said transmission has occurred primarily in smaller communities with historically lower vaccination rates, with no significant spread across major cities.

Opposition calls for stronger outreach

Opposition NDP health critic Sarah Hoffman said the latest increase highlights shortcomings in public health leadership.

“Seeing 27 cases since Friday is a huge, very quick uptake,” Hoffman said.

“I continue to be disappointed in how the government deals with public health.”

Hoffman said the province should be doing more direct community engagement.

“If the government wanted to act serious on measles immunizations, they would be empowering public health to get out there and meet with folks.”

She said public health experts had also warned earlier action was needed.

“Public health experts said this campaign needed to start a year and a half ago.”

“We’ve been the hot spot in North America with more cases in Alberta than the entire United States combined.”