Should You Get Another MMR Shot Amid Canada’s Measles Outbreak? Here’s What Experts Say

Toronto, April 30, 2025: With measles cases rising sharply across Canada, many Canadians are asking whether they need a third dose of the MMR vaccine. Health officials say the short answer is no, at least not for most people.

According to Health Canada, two doses of the MMR (measles, mumps, rubella) vaccine provide near complete protection. A single dose gives up to 95% immunity, while two doses offer about 99–100% effectiveness. For now, a third or “booster” dose is not recommended unless advised by a healthcare provider.

Those unsure of their vaccine status are encouraged to check with their doctors or request a blood test. Age also plays a key role. Canadians born before 1970 are usually considered immune due to likely natural exposure. Those born between 1970 and 1980 may have only received one dose, and those born after 1980 most likely got two doses during childhood or through school programs.

Travelers, especially to high risk countries, and healthcare workers should confirm their protection. Anyone born in 1970 or later and planning to travel may need to ensure they’ve had two doses.

As of mid April, Canada has reported over 1,000 measles cases, with outbreaks linked to provinces like New Brunswick, Ontario, Alberta, and Quebec. Many of these cases have connections to international travel from countries such as India, Uganda, Pakistan, Mexico, and Romania.

Symptoms of measles include fever, cough, runny nose, and red, watery eyes, followed by a distinctive rash that spreads across the body. It is extremely contagious and can remain airborne for up to two hours after an infected person leaves a room. Complications may include pneumonia, ear infections, encephalitis, and even death especially in children under five, pregnant individuals, and the immunocompromised.

Some people may still get measles despite being fully vaccinated, but such cases are rare and usually less severe. Health officials strongly discourage so called “measles parties” that deliberately expose children to the virus, warning of serious health risks and contribution to outbreaks.

The Public Health Agency of Canada emphasizes that vaccination remains the strongest defense. If you’re unsure of your immunization status, seek guidance from your health-care provider or get tested for immunity.