Public health unit perspectives on challenges, barriers, and lessons learned from Ontario's 2024-2025 measles...

To systematically gather perspectives from public health units (PHUs) on the challenges, barriers, and lessons learned from the multi-jurisdictional measles outbreak in Ontario (October 2024-October 2025).

We conducted a mixed-methods survey in June/July 2025. We invited PHU staff involved with the measles outbreak and the Ministry of Health to respond to an online engagement survey. We analyzed multi-choice and ranked questions using counts and proportions. For open-ended questions, we conducted an inductive thematic analysis to identify common themes.

We included 26 survey responses (83% response rate). At the time of the survey, about two-thirds (68%) of participating PHUs had at least one outbreak-associated case reported since October 2024. Respondents identified the lack of a comprehensive immunization registry (69%), immunization coverage below herd immunity thresholds (39%), workload demands or competing priorities (39%), and excluding susceptible contacts from school or work settings (39%) as their main challenges/barriers. For preparedness and response activities, respondents identified increased human resources capacity (63%) and use of technological tools (38%) for case and contact management as their most impactful strategies, along with enforcement or expansion of provincial school immunization legislation (42%). Lessons learned focused on timely and efficient outbreak response, supporting readiness, modernizing data systems and adopting technological innovations, standardizing and streamlining protocols, community engagement and relationship building, and strategic communications.

Further public health efforts will be needed to continue to strengthen Ontario's immunization, surveillance, and outbreak preparedness and response actions. These will also contribute to Canada regaining its measles elimination status.