At the June 18th Board of Health Meeting, Chief Medical Officer for the combined Haliburton Kawartha Northumberland and Peterborough Board of Health Thomas Piggott raised the topic of the measles in the region.
Earlier this month, two case of measles were diagnosed in Peterborough and one in the City of Kawartha Lakes. Peterborough Public Health and the Haliburton Kawartha Northumberland Board of health are in the process of merging. These health organizations were among a group of nine health units that are merging into four new entities. The objective was to address long-standing issues in the provincial health care sector, including capacity limitations, performance inconsistencies and staff recruitment and retention issues within the units.
In 1998, Canada was considered measles-free, which means that transmission of the virus was no longer a general risk as outbreaks were sporadic and limited to specific regions. That status is in jeopardy, as Canada now has outbreaks in any parts of the country, and in May, it had more measles cases than any other country in the Americas, according to CBC. Measles cases in Ontario are concentrated in southwest Ontario in communities with low vaccination rates.
Dr. Natalie Bocking, Deputy Medical Officer of Health for the combined Hali-burton Kawartha Northumberland and Peterborough Board of Health, explained that based on provincial data, there have been more than 2,000 cases in 2025, which is the highest number in decades. The vast majority of them are associated with an outbreak in South-western Ontario; a few cases relate to travel with a few others where the transmission source is unknown. Roughly 94% of the cases are people who are unvaccinated and more than 140 of those infected required hospital admissions. Most of these were youth and infants. There are currently 19 health units impacted from the outbreak in Southwestern Ontario. The three local cases are considered ‘breakthrough cases’ where vaccinated individuals have acquiring measles because the vaccine is not 100 per cent effective.
When the health unit is informed of a potential measles case, staff work to identify exposure and who is at highest risk. Their second priority is to prevent the spread of the virus and focus on exposure locations, identifying who is susceptible and offering vaccination.
Because measles has been so rare, residents are not very familiar with its symptoms, which can appear seven to twenty one days after exposure. They include fever, cough, runny nose and red, watery eyes. The trademark rash usually takes another few days to surface and usually starts on the face and spreading to the rest of the body. The virus is transmissible from 4days prior to the onset of symptoms to 4 days after the rash, so infected people can be spreading the virus before they realize they are infected themselves. Immunity is established by vaccination or a previous measles infection. Having two doses of a measles vaccination is almost 100% effective at preventing infection. In the rare case where a vaccinated person becomes infected, their symptoms remain relatively mild. The virus is extremely contagious: 90% of people who are exposed and are not immune become infected. Complications are rare but severe, and include brain inflammation which can lead to deafness, brain injury and even death.
Children under five, particularly infants, pregnant women and people with weakened immune systems face the highest risk of complications.
While new infections began to decline in June, the risk of infection remains. Canadians are encouraged to check their vaccination status to minimize their risk.