Five cases of measles have been confirmed in Canada so far this year, compared with a total of 12 cases identified in all of 2023, raising concerns over falling vaccination rates and the possibility of wider outbreaks.
On Friday, Toronto Public Health announced the most recent confirmed case, in a baby who is now in the hospital. The infant had recently travelled outside of Canada, according to a news release.
Measles, a highly contagious virus that can lead to severe complications, has been detected elsewhere in Ontario, as well as in Saskatchewan and Quebec.
Last month, health officials said there was one case of measles in a Saskatoon resident who had recently travelled outside of Canada. In Ontario, two other cases have been identified, including one last month in a vaccinated adult who recently travelled outside the country and another case this week in a child in the Peel region who had also travelled.
Last week, Montreal health officials confirmed a case in a child who had travelled outside the country.
“This is a much more contagious disease than we’re used to dealing with. It is a much more deadly disease than we have been speaking about recently, at least for children,” said Jeff Pernica, head of the division of infectious disease and associate professor of pediatrics at McMaster University in Hamilton.
Dr. Pernica said that individuals with measles are at their most contagious before the onset of the rash, which is a hallmark symptom of infection with the virus.
“The average person can be in a lot of rooms until somebody twigs to the idea that they have measles,” he said.
Last year, there were 12 cases of measles in Canada, according to the Public Health Agency of Canada.
Measles is no longer endemic in Canada, meaning cases are acquired internationally and brought here. But there are still risks of outbreaks, particularly among unvaccinated groups. This concern has taken on new significance in light of a surge of measles cases in Europe so severe that Britain has declared it to be a national incident.
The World Health Organization states that to keep measles outbreaks at bay, communities need 95 per cent of individuals to have had two doses of vaccine.
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There is no national vaccine registry in Canada, making it difficult to ascertain the up-to-date vaccination status of children and other groups. But the limited data that are available point to serious problems with vaccination rates, which experts say worsened during the pandemic, when routine childhood immunization clinics were interrupted and confidence in vaccines took a hit.
For example, as of 2022, only 74 per cent of Alberta children had received two doses of the measles, mumps and rubella vaccine by age 7, a decrease from 80 per cent in 2019, according to an online provincial database.
Experts say the percentage of vaccinated may be much lower in certain communities, which increases the risk of an outbreak if a measles case is introduced.
The virus is so contagious that almost every unvaccinated person who comes into contact with it will get measles. And measles can remain in the air for up to two hours after an infected person leaves a room.
Symptoms of measles can appear around 10 days after exposure, but the range can be one to three weeks. Symptoms can include a high fever, runny nose, watery eyes and red spots that spread from the face to the rest of the body.
About one in 1,000 people infected with measles will develop encephalitis, or brain inflammation, according to the Public Health Agency of Canada. One to three out of 1,000 will die as a result of measles.
Groups who are at higher risk for developing complications include children under 5, people who are pregnant and those with compromised immune systems.
Dr. Pernica said it’s important for people to check their vaccination status to prevent infection and spread.
“I don’t think we need to panic about measles,” he said. “I think what we need to do is make sure everybody is caught up to date.”
Carly Weeks