Doctors brace for potential measles surge in Calgary as Alberta's outbreaks drag on

Health experts are keeping a close eye on the measles situation in Calgary as case counts tick up and they're warning that vigilance is key.

With a new case reported in the Calgary health zone on Friday, the number of confirmed cases has nearly doubled in about a month after remaining relatively low and stable for several months.

As of midday Friday, the zone accounted for 44 of the province's 1,538 confirmed cases this year.

"We have more to come and I think that this is the tip of the iceberg," said Dr. Tania Principi, a pediatric emergency physician and associate clinical professor at the University of Calgary's Cumming School of Medicine.

She's seeing an increase in Calgary children with measles. And they can be very sick, she warned.

"A lot of these kids get quite significant pneumonias, trouble breathing. They've needed to go to the ICU," she said.

"Measles is dangerous. People can die from it.... You can have brain damage from it. So it's not just like a cold."

Measles is highly contagious and can hang in the air for several hours after a person leaves a location. The virus can lead to serious complications including pneumonia, brain inflammation, premature delivery and even death.

And there is no treatment for measles, according to Principi.

"I'm worried, to be honest.... People start spreading measles even before they know they have it," she said.

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She expects to see a bigger surge in the coming weeks.

"With festivals,... people travelling and vacation, I anticipate that we're going to see a lot more measles especially in Calgary, but throughout the province, [through] the summer and as kids go back to school in the fall," said Principi.

"The only way we can stop the spread is ensuring that people are vaccinated and if people do have symptoms that they stay home. But otherwise unfortunately this is going to continue to spread and our numbers are going to continue to increase."

Vaccination rates

"My level of concern is very high. And Calgary, and the north, are at the top of that concern," said Dr. James Talbot, a former chief medical officer of health for Alberta.

He made the comments in response to a question from CBC News at a recent expert panel hosted by the Alberta Medical Association.

While the north and south health zones continue to be the hardest hit parts of the province, Talbot sees worrying signs in Calgary. 

Some of the locations identified in the most recent Alberta Health Services measles exposure advisories include the emergency department at Alberta Children's Hospital, the ER at South Health Campus and the Glenmore Landing location of Alberta Precision Laboratories.

"Calgary has amongst the better immunization rates in this age group, but it's well below the 95 per cent that's required for protection."

According to provincial data, 74 per cent of children in the Calgary zone who turned two years old in 2024 were up-to-date with two doses of the measles vaccine. The provincial average was 68 per cent.

That vaccination rate has, so far, prevented community-level transmission, according to the University of Calgary's Craig Jenne.

"Because we're not truly at herd immunity, there is a risk that the virus can find an under-vaccinated population in the city and maintain some spread," said Jenne, a professor in the department of microbiology, immunology and infectious diseases.

"We have to be quite aware of that and hopefully we can stay on top of contact tracing, exposure alerts and anybody that may be at risk of contracting measles, and has been exposed, can self-isolate and get help as needed to really reduce the risk of this getting a foothold in the city."

Jenne said a lot of the cases in Calgary appear to be travel-related because locations such as hotels and the airport have been included in AHS exposure alerts.

The more cases that are brought into the city, the more likely the virus will find under-vaccinated groups and spark more widespread transmission in Calgary, he warned.

"Unfortunately the more times it's challenged, the more cases that appear, the more likely it is the virus will find a little daylight and be able to spread," said Jenne, who's also the deputy director of the Snyder Institute for Chronic Diseases.

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Visitor restrictions 

Meanwhile, visitor restrictions are in place at some Alberta hospitals now, as health officials work to reduce the risk of measles spreading to vulnerable patients.

Alberta Health Services (AHS) said temporary limits can be put in place in locations including pediatric hospitals, cancer treatment sites, labour and delivery units, as well as neonatal intensive care units and pediatric intensive care units

AHS says it's up to zone leadership to decide on a case-by-case basis whether to implement these restrictions and compassionate exemptions will be considered.

"As the measles situation continues to be dynamic, this approach allows zone leadership to determine whether restrictions are needed to support the well-being of patients," spokesperson Kristi Bland said in a statement emailed on Friday.

"In areas such as Edmonton and Calgary, where measles cases currently remain low, these precautions may be implemented due to the potential risk posed by visitors from regions with substantial measles circulation. They are not a response to increased risk or transmission within Calgary or Edmonton."

AHS has so far not specified to CBC News which hospitals have actually put these measures in place.