Measles has been spreading rampantly across parts of Alberta all spring and now, the province’s health authority has issued a second standing measles exposure advisory.

The idea is that people in certain communities should assume they are at risk of catching the most contagious disease in the world at any time.

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.

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

The Alberta Health Services (AHS) north zone is the least-vaccinated region in the province, according to the government’s own immunization data.

AHS says cases are growing in the province’s northwest region, particularly in the communities of La Crete, Fort Vermilion and High Level.

“This includes cases in individuals with no known exposure source, suggesting underreporting and a broader potential risk of measles transmission across the region,” AHS said on Thursday.

“This standing advisory will replace the use of separate site-specific exposure advisories, which no longer accurately capture the scope of potential risk at this time in the zone.”

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As of noon on June 12, there were 134 lab-confirmed cases, and 22 of those came in the past 24 hours. However, AHS said the actual scope of the outbreak is likely much larger.

Because of that, AHS is issuing a standing measles exposure advisory, effective immediately and until further notice, for the following communities:

• The Hamlet of La Crete
• St. Theresa General Hospital in Fort Vermilion
• Northwest Health Centre in High Level

Anyone who lives, works, attends school in, or is travelling to those areas are strongly advised to be aware of the increased risk for measles and to ensure their immunizations are up to date.

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At this point, anyone who goes to La Crete, Fort Vermilion and High Level and was born in or after 1970 and has fewer than two documented doses of measles-containing vaccine, may be at risk for developing the deadly disease.

They should monitor for symptoms of measles and are strongly encouraged to review their immunization records.

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2nd standing measles exposure alert in Alberta

Both the northern and southern portions of Alberta are now under the standing exposure advisories.

On May 23, AHS issued the same alert for the southeastern section of Alberta that includes the cities of Lethbridge and Medicine Hat.

The south zone of Alberta has now recorded 606 cases, including five in the past 24 hours.

Across Alberta, there are five people hospitalized with the measles, including one person in the ICU.

The recommended schedule for measles immunization is two doses: the first at one year of age and the second at 18 months.

At this time, AHS said babies in the south and north zones are eligible for additional immunizations: infants who are six months up to and including 11 months of age are recommended to receive an early dose of vaccine. However, they should still receive their routine two doses after they reach one year of age.

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Of the 868 confirmed cases across the province, 247 are in kids under the age of five, another 403 cases are in children ages five to 17, another 214 are in adults 18 to 54, and four cases have been confirmed in adults over 55 (a number that has remained unchanged for several weeks), according to the province’s dashboard. It is updated daily, Monday through Friday.

Of the 868 cases of which the province is aware, all but 29 are past the period of communicability, but that only applies to infected patients who have been tested.

If you think you have been exposed and you are not protected against measles, AHS said you may be able to receive immunization to reduce the risk of infection.

“A dose of vaccine needs to be given within 72 hours of exposure to prevent measles. Babies under one year of age, people with severely weakened immune systems, and those who are pregnant may be able to receive immunoglobulin within six days of exposure to prevent disease,” AHS said.

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Many measles exposure alerts in recent weeks have come from sick people visiting medical centres and doctors’ offices.

Call the measles hotline at 1-844-944-3434 for more information if these situations apply to you or your family.

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.

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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.

— with files from Katie Dangerfield, Global News and The Canadian Press