Ontario Health Officials Target Vaccination and Communication Amid Rising Measles Cases
Health officials in three Ontario regions hardest hit by the measles outbreak are ramping up efforts in communication and vaccination as case numbers continue to climb.
Public Health Ontario reported 89 new measles cases since March 26, bringing the total number of confirmed and probable cases in 2025 to 655. The surge has been linked to a travel-related case from New Brunswick.
“The sharp increase… is due to continued exposures and transmission among individuals who have not been immunized,” the report noted.
The Southwestern Public Health region — including St. Thomas, Woodstock, and Elgin and Oxford counties — saw the largest jump with 43 new cases. Dr. Ninh Tran, the region’s Medical Officer of Health, emphasized that vaccination remains the most effective protection against measles, one of the world’s most contagious illnesses.
“Unlike the flu or COVID vaccine, which mainly reduce severity, two doses of the measles-containing vaccine prevent infection altogether,” said Tran. His team is prioritizing vaccination for those considered susceptible — people who have never had measles or who haven’t received both doses of the MMR vaccine.
The MMR vaccine, which protects against measles, mumps, and rubella, uses a weakened virus to build lifelong immunity in healthy individuals, according to health officials.
Despite rising numbers, the true case count may be higher, as not all individuals with measles seek testing or medical care.
In the neighboring Grand Erie Public Health region — covering Brantford and surrounding rural areas — officials held a pop-up vaccination clinic above a Caledonia hockey arena this week.
Among attendees was Rachel Vaarkamp, who brought her five-year-old son, Tyse. “We don’t have a family doctor right now and realized it was time for his vaccinations. When we saw there were measles cases in the area, we wanted to get it done,” she said.
Sarah Titmus, who helped run the clinic, noted that while most people are receptive, vaccine hesitancy still exists. “We provide the most evidence-based information we can, so people can make informed choices,” she said.
Meanwhile, the Chatham-Kent Public Health Unit reported four new cases since March 26. Officials there are focusing on education and post-exposure support. In an innovative approach, Chatham-Kent Health Alliance hosted educational sessions in an isolation room, separate from hospital emergency areas, to reduce the risk of transmission.
“We could accommodate large groups without exposing others in our waiting rooms,” said Adam Topp, CEO of the Alliance. Attendees received guidance on quarantine protocols and were offered vaccination or immune treatments like post-exposure prophylaxis (PEP), which includes immune globulin injections to reduce infection severity.
