The sharp increase in measles cases in Ontario – including another 89 last week – underscores the urgent need for an electronic system to record vaccinations, public health experts say.
According to new data released by Public Health Ontario on Thursday, Ontario recorded a total of 661 measles cases (520 confirmed, 121 probable) associated with an outbreak in 13 public health units between Oct. 18 of last year and April 2, 2025.
The majority of cases have been among unimmunized individuals in the Southwestern Public Health and Grand Erie Public Health units. In its own measles report released Thursday, Southwestern said it had recorded 18 cases in the past seven days and 306 since last October.
Measles, a highly infectious airborne disease, is a major concern for Canadian public health officials – a stark contrast from when the country declared the illness eliminated in 1998 thanks to high immunization coverage.
Data points to a worrisome trend: Childhood immunizations are on the decline. A recent study published in the Canadian Journal of Public Health found a decline in childhood measles vaccination coverage in 2023 compared with 2019. Among seven-year-olds, the drop was nearly 11 per cent.
The way vaccinations are currently recorded in the province is also a concern for health researchers.
In Ontario, public health is not automatically alerted when a vaccination is administered; parents or health care providers must notify local health units, which often doesn’t happen. Records of immunizations are mainly tracked in the small yellow booklets given to parents and patients.
“It’s almost unacceptable that in this day and age we do not have a digital solution,” said Valerie Grdisa, chief executive officer of the Canadian Nurses Association. She added that it is shocking that in 2025 the system is not more integrated.
Jeffrey Pernica, associate professor of pediatrics at McMaster University in Hamilton, said having up-to-date information on who is vaccinated is of “critical importance when there is an outbreak of the most infectious disease known to humanity.”
Ideally, he said, an immunization registry would document all vaccines given by providers throughout a person’s life, and that individuals, physicians plus local and provincial public health authorities could access it.
Dr. Pernica is also the co-chair of the Ontario Immunization Advisory Committee. Last fall, it released a position paper for Public Health Ontario that urged the province’s Health Ministry to develop and implement such a registry. Doing so, it argued, would reduce the burden of vaccine-preventable diseases on individuals and the health system, make the province’s immunization programs more efficient and allow for better use of health resources.
The committee’s report also detailed how its call for a registry is far from new.
“We have been talking about this in Ontario for literally decades,” Dr. Pernica said. “I don’t know if there are any cogent, reasonable arguments against developing a vaccine registry.”
Vinita Dubey, an associate medical officer of health with Toronto Public Health who is also on the committee, said that while a vaccination registry sounds mundane, it is critical. During an outbreak, a registry can help officials quickly determine who is vaccinated or not to help prevent further spread, she explained.
Ema Popovic, a spokesperson for Ontario Health Minister Sylvia Jones, said local public health units collect immunization information and a central database called Panorama records routine vaccinations. The province is working with partners to digitize vaccination records and enable secure and more easily available searches, she added.
The limitations of Panorama have been well documented. In 2014, the Office of the Auditor-General of Ontario highlighted issues with data accuracy and said providers need to be able to electronically record vaccinations when they are administered.
The Ontario immunization committee used Manitoba’s system for documenting vaccinations as a case study in its position paper. That province has an integrated, electronic information system that allows for communicable-disease surveillance and outbreak management.
