NORTHERN ONTARIO — A measles outbreak is unfolding across Ontario at an alarming rate, with confirmed cases now emerging in Northern Ontario for the first time in decades. Public health officials are on high alert as they scramble to contain the highly contagious virus that has already spread rapidly through southern parts of the province.
First Confirmed Case in North Bay Since 1995
North Bay has confirmed its first case of measles in 30 years, marking a significant milestone in the resurgence of the virus in the province. The North Bay Parry Sound District Health Unit made the announcement on Friday, emphasizing the importance of vaccination in preventing further spread.
“Measles is a highly contagious virus that spreads through the air and can linger in a space for up to two hours after an infected person has left,” said Shannon Mantha, executive director of clinical services and chief nursing officer at the health unit. “While the immediate local risk remains low, the outbreak in southern Ontario demonstrates how quickly the virus can spread.”
The infected individual, an unvaccinated adult, was exposed to a confirmed case outside the district and is now in self-isolation along with close contacts. Health officials stress that no public exposure sites have been identified at this time.
Measles Cases Surging Across Ontario
According to the latest data from Public Health Ontario, 168 measles cases (146 confirmed and 22 probable) have been reported in 2025, surpassing the total number of cases recorded in all of 2024. In just the past week, Ontario and Quebec reported 61 new cases combined, signalling a sharp rise in infections. Most cases have been concentrated in southern Ontario, but Northern Ontario health units are now bracing for potential spread.
The Algoma District, Sudbury and Temiskaming health authorities are closely monitoring the situation, urging residents to check their vaccination records and receive their measles, mumps, and rubella (MMR) vaccine if they are not up to date. “The vast majority of people are immunized against measles, but because of how contagious this virus is, we need vaccination rates to be as high as possible,” said Dr. John Tuinema, acting medical officer of health for Algoma.
Highly Contagious and Dangerous: The Threat of Measles
Measles is one of the most infectious viruses known, spreading through airborne droplets when an infected person coughs, sneezes, or talks. A single case can infect up to 90 percent of unvaccinated close contacts. The virus can also survive on surfaces for up to two hours, increasing the risk of transmission in public places.
Symptoms typically appear 7 to 21 days after exposure and include: high fever, runny nose and cough, red, watery eyes and a distinctive rash that begins on the face and spreads to the rest of the body
Severe complications include pneumonia, hearing or vision loss, brain inflammation (encephalitis), and, in rare cases, death. Those at the highest risk include children under five, pregnant individuals, immunocompromised individuals, and those who are unvaccinated.
Vaccination Rates Falling: A Growing Concern
While vaccination remains the most effective defense against measles, immunization rates in parts of Ontario have fallen below the 95 percent threshold needed for herd immunity. The COVID-19 pandemic led to delays in routine vaccinations, leaving gaps in immunity across various age groups. In some regions, such as Sudbury, 76.2 percent of seven-year-olds have received both doses of the MMR vaccine, compared to the provincial average of 70.4 percent; both numbers are current and are well below the 95 percent MMR vaccinations required for herd immunity.
Health officials are ramping up vaccination efforts, offering additional clinics and urging residents to verify their immunization status. “If you’re unsure of your vaccination history, check with your healthcare provider or public health unit. If your records are unclear, another dose of the vaccine can be administered,” Dr. Tuinema said.
Read our related editorial: “Rise in once-forgotten deadly ills largely preventable”
Protecting the North: What You Need to Know
With measles cases on the rise, Northern Ontario residents are encouraged to take the following precautions:
Ensure vaccinations are up to date: The MMR vaccine is safe, effective and typically administered in two doses, first at 12 months old and again between four and six years old.
Watch for symptoms: If you develop fever, cough, or a rash, contact your healthcare provider immediately and avoid public spaces.
Call ahead before visiting healthcare facilities: If you suspect measles, notify medical staff in advance so they can take precautions to prevent further spread.
Be cautious when travelling: Measles cases have been linked to international travel. If traveling, ensure you are vaccinated at least two weeks before departure.
The Road Ahead
As measles continues to spread across Ontario, public health officials remain committed to containing the virus and preventing further outbreaks. The resurgence of measles serves as a stark reminder of the importance of routine vaccinations and the role of community-wide immunity in stopping infectious diseases.
“We have the tools to prevent measles,” said Dr. Sarah Khan, an infectious diseases specialist at McMaster University. “Now, we need to use them. Vaccination is our best defense.”
For the latest updates on measles cases and vaccination clinics in Northern Ontario, residents are encouraged to visit their local health unit websites and stay informed.
As of March 8, Public Health Sudbury District has not reported any cases of measles.
