The Sudbury and District Health Unit says a child confirmed to have the disease may have exposed people in a handful of locations at specific times between April 23 to 25.
The locations are Costco, the LaSalle All Day Walk-in Clinic and the Health Sciences North emergency department.
Health officials say anyone at the sites during the possible exposure window should ensure that children under the age of 18 have had two doses of the measles vaccine.
They're also encouraged to contact the health unit if they had an infant with them or are unsure of their immunization status, among other conditions.
They say people who have had two doses of the measles vaccine, or who have had measles in the past are protected from the highly contagious virus that causes the disease.
The province said at the start of the month that there have been a number of small measles outbreaks with 11 confirmed cases so far this year.
Public health officials say measles is highly infectious and people can spread the disease before they are symptomatic.
Measles causes high fever, cough, rash, runny nose and watery eyes, can be complicated by ear infections or pneumonia and causes death in one in about 3,000 cases.
(The Canadian Press, CJMX)