Ontario measles cases approaching high set a decade ago

The number of confirmed cases of measles in Ontario in just over four months of the year is nearing a high number set a decade ago in the province, according to data from an provincial government agency.

Dr. Isaac Bogoch, an infectious diseases consultant at the Toronto General Hospital, said measles is clearly on the rise in Ontario, with most of the cases related to travel or to contact with a person who has travelled.

As of May 8, there were 21 confirmed cases of measles in Ontario, while in 2014, there were 22 confirmed cases of measles in the entire calendar year, according to Public Heath Ontario.

"This is problematic," Bogoch said on Wednesday.

"This is a very contagious infection, and if the virus enters a community that has lower vaccine rates, where there is a high proportion of undervaccinated or unvaccinated people, we can see explosive outbreaks. The goal is obviously to prevent that from happening."

Of the 21 confirmed cases this year, all were in people born after 1970.

Thirteen of the 21 cases were in children, 12 of whom were unimmunized. Five of the cases required hospitalization. All of those hospitalized were unimmunized children. One of the five hospitalizations required admission to an intensive care unit.

According to Public Health Ontario, 15 of the 21 confirmed measles cases this year in Ontario were associated with travel. The cases occurred in nine different public health units in the province.

Bogoch said a rise in the number of cases around the world is equally significant.

"Globally, there are so many cases of measles that we are bound to import it," he said.

Bogoch said measles kills about 130,000 people around the world every year and the vast majority of those who die of the disease are children.

He said a growing number of people choosing not to get vaccinated may be contributing to a rise in cases.

People should check their vaccine records to ensure they have the recommended two doses of the measles vaccine, especially those planning to travel to other countries where vaccine rates may be low, he added. 

"We've been able to keep many of these illnesses at bay for decades with effective public health programs and high rates of vaccination. But to no one's surprise, when you start to see vaccine rates slip, we're going to start to see the resurgence of these infections again," he said.

"This is not the benign infection that so many people say it is."

Public Health Ontario, in a May 9 enhanced epidemiological summary on measles, said: "In Ontario, measles has been rare, owing to the successful elimination of measles in Canada and high immunization coverage.

"Due to an increase in measles activity globally, Ontario has begun to see more cases of measles."

On Tuesday, Peel Public Health reported a confirmed case of measles in an adult from Mississauga.