Grey Bruce Public Health is advising the community of a potential measles exposure location, identified during a contact-tracing investigation into a laboratory-confirmed case of measles in a Grey-Bruce resident.

The case, whose vaccination status is unknown, attended the emergency department at Brightshores Health System’s Owen Sound Hospital at approximately 9:30 p.m. on Wednesday, April 2, 2025. The case remained at the hospital until about 6:30 a.m. on Thursday, April 3, 2025.

The measles virus can survive in the air and on contaminated surfaces for up to two hours after an infected person leaves an area.

Grey Bruce Public Health and Brightshores Health System collaborated over the weekend to contact all registered patients who were at the emergency department within the exposure window – 9:37 p.m. on April 2 to 8:28 a.m. on April 3. However, individuals who were not registered, but were in the emergency department during this exposure window may not have been identified and contacted.

Anyone who was present in the emergency department within the exposure window is advised to do the following:

•    Confirm vaccination status. Ensure all individuals in the household are up to date on measles vaccination. In general, those born before 1970 are considered immune against measles. Two doses of a measles-containing vaccine are recommended for anyone born after 1970. If unsure of vaccination status, individuals should check with their healthcare provider or ICON.

•    If not protected against measles, individuals should contact their healthcare provider or Public Health to receive post-exposure treatment, if it’s been six days or less since exposure, or to receive a measles-containing vaccine for lifelong protection.

•    Monitor for measles symptoms, which generally start 7 to 21 days after exposure. Symptoms can include high fever, cold-like symptoms (cough/runny nose), sore eyes, and sensitivity to light. About three to seven days after symptoms begin, a rash typically appears. The rash looks like red spots and blotchy patches that start on the face then spread down the body, arms and legs. 
•    If an individual develops measles symptoms, they should immediately isolate at home and call a healthcare provider. Household members who are not immune to measles should also stay home during this period and consult with public health. If medical care is required, call ahead to a healthcare facility before arriving in-person, so the facility can take precautions to prevent the virus from spreading to others.
Ontario is currently experiencing a multi-jurisdictional measles outbreak. As of April 2, 661 measles cases have been reported in 13 Public Health Unit areas. About 95% of the cases did not have immunity to measles or had unknown vaccination status.

The latest Grey-Bruce case is believed to be linked to travel outside of the area.

Measles can spread easily when an infected person coughs, talks, or sneezes, and another person breathes in virus particles. People with measles can be infectious from four days before to four days after the rash begins.

Vaccination is the best defence against measles. The efficacy of a single dose of a measles-containing vaccine is estimated to be 85% to 95%. With a second dose, efficacy is almost 100%.

As part of Ontario’s publicly funded vaccine schedule, babies should receive a measles vaccine at one year of age and children should receive a second dose ages 4 and 6.
Vaccination is also publicly funded for adults if they have never had measles or been vaccinated.
Adults born before 1970 are generally presumed to have acquired natural immunity to measles; however, susceptible healthcare workers, travellers to places outside Canada, and military personnel should receive a measles vaccine, regardless of birth year.
Infants aged six to 11 months, children aged one to four years, and adults aged 18 or older, born on or after 1970, may be eligible to receive an additional dose of a measles-containing vaccine if they live or will be travelling to an area experiencing a measles outbreak.
Most people who contract measles recover without treatment in two to three weeks, but the virus can be more severe for infants, pregnant women, and those with compromised immune systems. Measles may cause complications, such as pneumonia, brain swelling (encephalitis), or seizures, and, in rare cases, death.

More information about measles is available on the following webpages:

•    Grey Bruce Public Health Measles webpage.

•    The Ontario Ministry of Health Measles webpage or Measles Fact Sheet.

•    Health Canada Measles webpage.