Updated at 10:45 p.m.

Yellowknife Catholic Schools has announced that both Weledeh Catholic School and St. Pat's High School will be closed on Monday due to the confirmed case of measles that was made public on Sunday evening. 

A letter signed by YCS superintendent Adam Murray stated that the decision was made to close both schools "while we verify that an adequate number of staff have proof of measles vaccination to ensure the schools can operate safely as per direction from the Chief Public Health Officer."

Murray also stated that there would be an update from the board on the situation at 2 p.m. Monday afternoon.

The original letter was sent out by administration at St. Pat's informing parents that their child may have been exposed beginning late last month. 

"Your child may have been exposed on April 28, April 30, and May 1, 2025," reads the letter.

The affected area includes any shared areas with Weledeh Catholic School, the letter adds, and the possible exposure would've occurred between the hours of 8 a.m. and 5:40 p.m. on each of the days included.

The letter included a notification from Dr. Kami Kandola, the territory's chief public health officer, who wrote that anyone who was in the area is considered to have been exposed.

According to a letter that accompanied the email, the symptoms of measles typically include:

• Fever

• Dry cough

• Runny nose

• Sore throat

• Inflamed eyes (conjunctivitis)

• A skin rash made up of large, flat red blotches, usually starts on the face and spreads to the rest of the body and lasts between four to seven days

Measles is an extremely transmissible and highly infectious disease and can affect nine out of 10 people. It's spread through the air when an infected person coughs or sneezes and others can become infected when they breathe in air or touch a surface contaminated with the virus.

The measles virus can remain in the air for up to two hours once an infected person leaves the affected area and can be spread by a person four days before the rash until four days after the rash appears. 

What that means is if you have the virus, you could spread it without knowing you have it in the first place.

If you and your child have received two doses of the MMR vaccine, you should be fine because you're protected from the virus. If you or your child received your two doses outside the NWT, the letter states you'll have to send a copy of the immunization record to Yellowknife Public Health.

If there is no proof of immunization or you or your child have not received two MMR doses, the school is telling students to stay at home until they're contacted by public health.