Durham health unit reports possible measles exposure at Oshawa urgent-care clinic March 4; total cases now three

Durham Region Health Department says members of the public may have been exposed to measles at Ritson North Medical (Urgent Care) in Oshawa on March 4, 2026, between 3 p.m. and 5:15 p.m. The health unit also confirmed on March 8 that two additional measles cases were identified in local unimmunized children.

The advisory affects anyone who was at the clinic during that time window, because the health unit is asking potentially exposed people to monitor for symptoms through March 25, which it says is 21 days after the exposure.

The health unit reported that the two new cases bring Durham Region’s total to three confirmed measles cases, all in one household.

Durham Region Health Department linked the March 4 exposure window to the two newly confirmed cases. The clinic—at 1288 Ritson Road North in Oshawa—had also been identified previously as an exposure site on Feb. 26 and March 2, the health unit said.

The health unit said it is investigating and following up directly with known contacts in Durham Region who may have been exposed.

For people who believe they were exposed, the health unit advises checking that they and their family members have had two doses of measles vaccine (MMR or MMRV). It also says people born before 1970 would likely have had measles as children and are protected. Anyone unsure of their vaccination status should check with a health-care professional, the health unit said.

If symptoms develop, the health unit advises people to stay home and not go to work or school. It also advises calling ahead before visiting a clinic or hospital to let staff know about a possible measles infection. The health unit also advises wearing a well-fitting mask when getting a medical assessment.

Measles is a highly contagious disease that spreads easily to people who are not immunized or who have not previously had measles. The health unit says infants under one year old, unimmunized pregnant individuals, and people with weakened immune systems are at increased risk of complications. The virus can remain in the air or on surfaces for up to two hours.

The health unit says measles symptoms typically begin seven to 21 days after infection and may include:

• High fever (38.3°C or higher)
• Cough
• Runny nose
• Red, watery eyes (conjunctivitis, also known as pink eye) and sensitivity to light
• Red rash lasting four to seven days

Durham Region posts a list of exposure sites at durham.ca/Measles. Public Health Ontario also maintains a provincial list on its “Measles Exposures in Ontario” webpage.