Confirmed Measles Case in Grey-Bruce; Risk to Public Considered Low
An isolated measles case in Grey-Bruce has been confirmed in an unvaccinated child. No public exposures identified, and officials say community risk remains low amid rising cases across Ontario.
Grey Bruce Public Health (GBPH) has confirmed a case of measles in an unvaccinated child in the region, marking the first laboratory-confirmed case locally amid a broader surge in cases across Ontario.
According to a March 21 media release from GBPH, the affected child and household members are currently isolating at home. No other members of the household have shown symptoms of measles, and all others had previously received the measles vaccine.
A contact-tracing investigation has found no evidence of exposure risks in public places or local schools, and GBPH officials say the risk of community transmission is low.
“Grey Bruce Public Health has been in contact with the family and relevant healthcare partners and managing this situation since we received the report of measles-related symptoms,” said Dr. Ian Arra, Medical Officer of Health and CEO of Grey Bruce Public Health. “At this point in our investigation, we believe the risk of transmitting the virus from this case to others has been well contained.”
GBPH noted that the case is not related to recent travel and is likely connected to the ongoing multi-jurisdictional measles outbreak in southern Ontario.
The confirmation comes amid a rise in measles cases both in Ontario and across the country. As of March 18, the Public Health Agency of Canada reported 369 measles cases nationwide in 2025. However, the actual number is expected to be higher due to recent updates. Ontario alone has recorded at least 470 cases since October 2024, according to provincial data.
Measles is a highly contagious airborne virus that can linger in the air and on surfaces for up to two hours. It spreads easily when an infected person coughs, sneezes, or talks, and others inhale the virus particles.
Symptoms usually begin 7 to 21 days after exposure and may include high fever, cough, runny nose, sore eyes, and a rash that starts on the face and spreads to the body. Infected individuals can be contagious from four days before to four days after the rash appears.
Vaccination remains the most effective protection. According to GBPH, a single dose of a measles-containing vaccine provides 85% to 95% immunity, while two doses offer nearly 100% protection. Under Ontario’s immunization schedule, children should receive the first dose at one year of age and the second between four and six years.
Adults born after 1970 are advised to ensure they’ve received two doses. Vaccination is publicly funded for eligible adults who have not been vaccinated or previously infected.
As measles outbreaks continue in other parts of Ontario — including Huron-Perth, Grand Erie, and Southwestern Public Health regions — the Ministry of Health recommends accelerated vaccination for those at higher risk, including infants aged 6 to 11 months and children who have only received one dose.
While most people recover from measles within two to three weeks, the disease can lead to serious complications such as pneumonia, encephalitis (brain swelling), and, in rare cases, death — especially among infants, pregnant individuals, and people with weakened immune systems.
GBPH advises individuals who suspect they may have measles to call ahead before visiting any healthcare facility to prevent potential spread.
More information is available on the GBPH Measles webpage, as well as through the Ministry of Health and Health Canada.