Epidemiological review on the resurgence of measles outbreaks in Canada during the post-elimination era: A scoping review

In 1998, the World Health Organization declared that measles had been eliminated in Canada. Despite this status, Canada continues to experience sporadic outbreaks driven by importations from endemic countries. Understanding the post-elimination outbreaks is crucial for informing prevention and control policies. The purpose of this review was to identify and analyze epidemiological factors of measles outbreaks' resurgence in Canada. We conducted a PRISMA scoping review to compile epidemiological data from peer-reviewed articles and grey literature on outbreaks in Canada from 1999 to 2025. A total of 618 articles were retrieved from the 9 databases queried, and 144 grey literature items were collected in the manual search; including 18 peer-reviewed articles and 28 grey literature sources. Eighty distinct outbreaks with a total of 7,455 cases were reported between 1999 and 2025 where 61.7% of the outbreaks were associated with imported cases of measles and 79.7% of the cases had not received the Measles-Mumps-Rubella vaccine. More than 60% of the cases (5078) were related to the 2025 multijurisdictional outbreak. Post-elimination measles outbreaks in Canada are primarily caused by importation of the disease and subsequent transmission in local under-vaccinated communities.