Unvaccinated child with measles likely contracted in nearby community: GBPH

Public health nurse Lauri Bidinot demonstrates how to give a measles shot to a young girl at Southwestern Public Health in St. Thomas, Ont. on Tuesday, March 4, 2025. (Geoff Robins/THE CANADIAN PRESS)

Grey Bruce Public Health (GBPH) confirmed on Friday that a case of measles in a child in it’s jurisdiction has been confirmed in a laboratory.

The child and their family are isolating at home, and contract tracing has confirmed that there are no public places in the area where community members could have been exposed. GBPH confirmed that the child was unvaccinated.

“At this point in our investigation, we believe the risk of transmitting the virus from this case to others has been well contained,” affirmed Dr. Ian Arra, Grey-Bruce’s Medical Officer of Health and CEO of Grey Bruce Public Health.

032125_Measles GBPH london A scientist in microbiology laboratory working with bacteria culture (Manjurul/Getty Images)

The confirmed case is the only member of the household that did not have their measles, mumps and rubella (MMR) vaccine. No other members of the family have exhibited any symptoms.

GBPH said that the case was likely not acquired abroad, but is instead linked to an ongoing measles outbreak in southwestern Ontario.

At this time, the public health unit believes that the risk of acquiring measles in the area remains low, especially for those protected by vaccines.

“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%,” said GBPH in a statement.

032025_southwestern public health measles outbreak ontario London A sign outside Southwestern Public Health in St. Thomas, Ont. on Tuesday, March 4, 2025 warns residents to call ahead before visiting a doctor or hospital if they think they have the measles. THE CANADIAN PRESS/ Geoff Robins (Geoff Robins/THE CANADIAN PRESS)

If you live in or plan to visit an area experiencing a measles outbreak, it’s recommended that you ensure your vaccines are up to date. Currently Huron-Perth, Grand Erie (Haldimand-Norfolk, Brant County, Brantford), and Southwestern (Oxford, Elgin, St. Thomas) Public Health areas have been identified as areas of concern.

The virus is usually most severe for infants, pregnant people, and those with compromised immune systems.