Measles outbreak Slows in Southwestern Ontario: A Sign of progress?

Southwestern Public Health, the public health unit at the centre of Ontario’s measles outbreak, reported the fewest new weekly cases in months, signaling a potential turning point in the ongoing health crisis. Four new measles cases were recorded between June 12 and 19, marking the lowest seven-day count since weekly tracking began in late February.

Measles Cases on the Decline

After a surge that saw over 100 cases reported in a single week just over a month prior, the recent downward trend is being viewed as a positive sign. Dr. Ninh Tran, the unit’s medical officer of health, expressed cautious optimism, stating that the consistency of the decrease suggests a potential shift in the outbreak’s trajectory and indicates that public health interventions are having a meaningful impact.

Despite the encouraging trend, Southwestern Public Health remains vigilant, continuing its vaccination efforts, community outreach, and case management strategies.

Regional Disparities Persist

Since the outbreak’s onset in October 2024,Southwestern Public Health has documented 751 measles cases,accounting for approximately 34% of the 2,179 cases reported provincewide by Public Health Ontario. While the provincial agency’s data is reported two days earlier, the figures align consistently with the local health unit’s findings.

Provincially, measles cases increased by 96 between June 10 and 17, following a rise of 74 in the preceding week. Despite the downward trend in Southwestern Public Health, its rate of 317 cases per 100,000 residents remains considerably higher than the provincial average of 14 cases per 100,000, according to Public Health Ontario.

The four health units accounting for 67% of Ontario’s measles cases include Southwestern, Grand Erie (Brantford, Brant, Norfolk, and Haldimand), Huron Perth, and Chatham-Kent.

Neighboring Regions Cautiously Optimistic

The Middlesex-London Health Unit, bordering Southwestern public Health, has reported 47 cases since the outbreak began. After several weeks without new cases, nine new cases emerged in the past week.Associate Medical Officer Joanne Kearon noted that weekly totals have fluctuated recently, making it premature to confirm a clear downward trend.

While hopeful that the signs point to an end to the outbreak, the Middlesex-London unit emphasizes that it will take several weeks without new cases before the outbreak can be declared over, considering the incubation period and transmission nature of measles.

Did You Know? measles was declared eliminated in the United states in 2000, but outbreaks can still occur when unvaccinated individuals are exposed to the virus.

Measles Cases in Ontario Health Units