The measles virus lives in the nose and throat mucus of infected people. Photograph: Natalya Maisheva/Getty Images (https://www.theguardian.com/wellness/2025/may/02/measles-symptoms-vaccine-outbreak)
Measles is a highly infectious disease caused by the measles (rubeola) virus. Some people think of measles as just a little rash and fever that clear up in a few days. But measles can cause serious health complications, especially in children younger than 5 years old. Measles is highly contagious. If one person has it, up to 9 out of 10 people nearby will become infected if they are not protected.
Symptoms of measles
Symptoms can appear 7 to 21 days after being infected with the measles virus.
Initial symptoms include:
- fever
- cough
- runny nose
- red, watery eyes
About 3 to 7 days after symptoms begin, a rash appears. This rash looks like red spots and blotchy patches that start on the face, and then spread down the body, arms and legs.
The rash can last 4 to 7 days.
Most people recover from measles within 2 or 3 weeks.
Diagnosing measles
It’s very important to diagnose measles early to help prevent it from spreading to other people.
Health care providers may suspect measles based on your symptoms and your possible exposure to the virus. For example, they may ask you if:
- you’re aware of transmission in your community or had an exposure to someone with measles
- you’ve been vaccinated against measles or previously infected with measles
- you’ve recently travelled to a place where measles is present
A health care provider will likely collect a sample to confirm the diagnosis with a lab test, which may include:
- swabs from your nose or throat
- a blood test
- a urine test
Preventing measles
Measles can be prevented with routine vaccinations, which typically begins at 12 months of age. If you or your child missed a vaccine, you can still catch up.
Having 2 doses of a measles-containing vaccine is almost 100% effective at preventing measles. Two doses of measles-containing vaccine are recommended for children, adolescents and some adults. Check with your health care provider or local public health department about measles vaccination recommendations in your province or territory.
If you plan to travel outside of Canada, talk to a health care provider or local public health department preferably 6 weeks before travel to see if you are up to date with your vaccinations or need additional doses of a measles-containing vaccine. (https://www.canada.ca/en/public-health/services/publications/diseases-conditions/measles-what-should-know.html)
If you believe you or your family may have been exposed to measles and have not been vaccinated (or have not had a measles infection in the past), isolate and contact your health care provider or local public health department immediately for guidance.
If you develop symptoms of measles, isolate and call a health care provider immediately. The health care provider can arrange to see you while preventing the spread to others.
Help stop the spread of measles.
Talk to a health care provider or your local public health department if you are not sure if you or your family are up to date with recommended vaccines and to catch up on any missing vaccines.
https://www.canada.ca/en/public-health/services/diseases/measles/health-professionals-measles.html
https://trello.com/c/YFnwXObL/117-measles-factsheet-in-english
