Alberta has surpassed the United States in confirmed measles cases, after 30 new cases were diagnosed over the weekend.

Once declared eradicated in Canada in 1998, measles has made a comeback, spreading rapidly in recent months due to declining vaccination rates.

The province has now seen 1,314 cases since the beginning of March.

The U.S. Centers for Disease Control and Prevention has reported 1,288 cases so far this year across 39 states.

Joan Robinson, a pediatric infectious diseases physician at the Stollery Children’s Hospital in Edmonton, said there’s no reason Alberta should have this many cases.

“It is completely ridiculous,” she said, noting Alberta’s childhood immunization rates are below the threshold for herd immunity, which, for measles, requires at least 95 per cent of the population to be immunized.

Alberta government data on Monday showed of those with lab-confirmed cases, over 1,000 of them are not vaccinated.

The majority of those who have fallen ill are children and teenagers, who make up over 950 of the cases.

Dr. Robinson blames misinformation that spread during the COVID-19 pandemic, as well as parents these days not having been exposed first-hand to the horrors of measles.

“They’re maybe somewhat concerned that vaccines are bad, not realizing that measles is quite a severe infection. About one in 10 children with measles get admitted to a hospital. About one in 1,000 will get encephalitis, which is the inflammation of the brain, can cause long-term brain damage, and can certainly result in death,” Robinson said.

“I think parents don’t realize measles is a far more severe infection than COVID or influenza or chicken pox — all the infections they might be more familiar with.”

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Robinson said herd immunity is critical not just for protecting your own family, but also other children who can’t get vaccinated, such as those who have had a heart transplant or are undergoing chemotherapy.

“They’re at very high risk for measles even if they were immunized before they had the cancer or the transplant,” Robinson said.

“It can be incredibly frightening for these children and their parents to be exposed to measles.”

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1:45 Health experts warn of risks that large gatherings could pose to some Albertans during measles outbreak

Measles, known for its characteristic red rash, is one of the most contagious viruses on the planet, with an R number of 12 to 18 — meaning one infected person can spread it to up to 18 others in an unvaccinated population.

To put that in perspective, COVID-19’s original strain had an R number of about two to three, and even highly transmissible variants like Omicron rarely exceeded 10.

The outbreak of the highly contagious disease hasn’t led to any deaths so far in Alberta.

Three people, including two children, have died in the United States. Last month in Ontario, a premature infant died after being born infected with the highly contagious virus through the mother.

In that case, doctors said measles was a significant contributing factor, but the infant also had other serious medical complications unrelated to the virus.

The U.S. has also seen more hospitalizations than Alberta, with the CDC reporting 162 people have been hospitalized compared to just over 100 Albertans.

Summer events could lead to numbers growing

The numbers will likely grow in the weeks to come.

Dr. Karla Gustafson, medical officer of health for the Calgary Zone of Alberta Health Services, said the influx of people visiting the province to hike the Rocky Mountains or attend the Calgary Stampede (that just ended on Sunday) would 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 last week.

Over the last week and a half, Alberta hosted 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 circulate.

Already, both the AHS north and south zones have issued standing exposure advisories — the idea being people in certain communities should assume they are at risk of catching the most contagious disease in the world at any time.

1:41 2025 Calgary Stampede narrowly misses attendance record

Dr. James Talbot, a former chief medical officer of health in Alberta, 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.

Alberta is home to just under five million people, while the United States population is more than 341 million.

“For a province like ours to have more cases of measles than the entire United States, whose population is 70 times larger than Alberta’s, is not just shocking, it’s proof that Danielle Smith’s UCP government has failed us all,” said Opposition NDP leader Naheed Nenshi.

“This was not written in stone. With good public health measures, an immunization campaign and a minister who might have tried to stop it, this spread could have been prevented.”

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Global News has reached out to the Alberta government about the province’s latest numbers. This story will be updated if a response is received.

Measles can ‘erase’ your immune system’s memory

Measles is an extremely contagious disease and is spread easily through the air.

Symptoms include:

• Fever of 38.3° C or higher
• Cough, runny nose and/or red eyes
• A rash that appears three to seven days after fever starts, usually beginning behind the ears and on the face and spreading down to the body and then to the arms and legs. The rash appears red and blotchy on lighter skin colours. On darker skin colours, it can appear purple or darker than the skin around it, or it might be hard to see.

Complications of measles can include ear infections, pneumonia, inflammation of the brain, premature delivery, and rarely, death.

The highly contagious virus doesn’t just cause a rash and fever — it can also wipe out the immune system’s memory, leaving survivors vulnerable to infections they’ve fought off before, like the flu, a cold, or even diseases they’ve been vaccinated against.

Health Canada warns that measles can lead to serious immune suppression, known as immune amnesia. This can increase the risk of other illnesses and even raise the chances of death for months or even years after the infection, the health agency states on its website.

People who are pregnant or have weakened immune systems and babies under the age of one are at greatest risk.

If symptoms of measles do develop, individuals are advised to stay home and call Health Link at 811 before visiting any health-care facility or provider, including a family doctor’s office or pharmacy.

The measles vaccine is highly effective at preventing infection and complications, and is free to get in Alberta.

— More to come…

— with files from Hannah Alberga and Jack Farrell, The Canadian Press