Measles was rare in Ontario, with only 101 cases reported between 2013 and 2023 — until a surge in cases last year.

The province's chief medical officer of health is urging Ontarians to make sure they are immunized against the measles amid the most severe outbreak in the province in more than a decade.

Over 96 per cent of cases in Ontario are among individuals who are unimmunized, or have unknown immunization status, and were exposed in their community or while travelling.”