No measles confirmed in Ottawa: Public health monitoring re-emergence

More travel-linked cases of measles in GTA The latest case of measles in the GTA is in a child who travelled to Europe, with officials warning of possible widespread exposure.

Ottawa Public Health says there is a risk of re-emergence of measles, citing a rising number of cases in different parts of the world.

The risk can be mitigated through maintaining higher vaccination rates, the public health agency said in a statement to CTV News Ottawa on Wednesday.

“Through immunization programs, we’ve been able to significantly reduce the incidence of many of these diseases in Canada. However, there is a risk of re-emergence of vaccine preventable diseases like measles if high vaccination rates are not maintained,” said Dr. Laura Bourns, associate medical officer of health at OPH.

Dr. Bourns says currently there are no cases in the city, noting that the most recent case of measles in an Ottawa resident was in 2019.

“Between 2014 and 2019, there were nine confirmed cases of measles in Ottawa residents,” Bourns said.

Bourns added Wednesday afternoon that the latest data show most teenagers were protected against measles, but younger children still needed to catch up.

"The most recent measles coverage estimates for Ottawa (school year 2021-22), 95% among 17-year-olds (similar to pre-pandemic) and 59% among 7-year-olds (lower than pre-pandemic), are underestimates," Bourns wrote.

"In 2023, OPH administered approximately 25,000 catch-up doses of routine childhood immunizations to about 10,000 children and youth up to the age of 18 years through OPHs community clinics, Neighbourhood Health and Wellness Hubs and school clinics (both high school catch-up and targeted elementary). To date in 2024 (up to Feb. 14) OPH has administered a total of 4,767 doses of routine childhood vaccines to 2,276 children and youth 0-18 years through our community clinics, Neighbourhood Health and Wellness Hubs and targeted elementary and secondary school catch-up clinics."

How many cases are there in Canada?

According to the Government of Canada's website, currently there are three active cases of measles in Canada.

"Given this dramatic rise in cases globally, health system partners in Ontario must be prepared for the continued importation of cases and potential outbreaks," said Ontario's Chief Medical Officer of Health Dr. Kieran Moore in a statement.

"Importation and resultant local transmission can, and has, led to measles outbreaks in Canada."

A case of measles in a Montreal child was reported to officials on Tuesday. The infection was likely contracted during a trip to Africa, according to Montreal Public Health, and the infectious period is believed to have lasted from Jan. 29 to Feb. 6.

Meanwhile, in Toronto, an infant has been hospitalized after contracting the measles. Toronto Public Health confirmed in a news release last week that it is investigating a confirmed case of measles linked to travel. Few details have been released about the case, but officials say the infant is being treated at a hospital.

In October, two cases were confirmed in residents of the Outaouais region after returning to Canada from abroad. OPH said it reached out directly to anyone who was exposed to the cases. It did not say how many people it contacted, but in a statement to CTV News Ottawa attributed to Associate Medical Officer of Health Dr. Trevor Arnason, it said that it had been successful in reaching "almost all the Ottawa residents who may have been exposed."

When OPH contacts anyone who has been exposed to measles, they are advised to:

What is measles and who’s at risk?

Measles is highly contagious from four days before the rash to four days after the onset of rash. It is caused by the measles virus. The measles virus lives in the nose and throat of the infected person. People who come in contact with an infected person should monitor their symptoms for 21 days, OPH says on its website.

Infants under 12 months of age, unvaccinated pregnant women and people who are immunocompromised are at greatest risk for complications when contracting measles, according to Bourns.

Around nine out of 10 people who are not fully vaccinated against the disease may become infected if they become in close contact with an infected person, Bourns explains.

How to protect your children?

In Canada, it is the responsibility of parents and caregivers to ensure their children are protected.

“As part of the publicly funded routine childhood immunization schedule, measles-containing vaccines are typically given by primary care providers to children in two doses, at ages one and four-six years,” Bourns said.

“Two doses of measles vaccination are 99 per cent effective at preventing infection. Parents/caregivers who are unsure if their child is up to date with their measles vaccines are encouraged to speak with their regular health care provider and should also review their own immunization history for measles before travelling outside of Canada.”

Bourns adds that OPH has implemented the necessary measures to make sure every child is protected.

“Children who do not have or cannot access a regular health care provider can book a routine vaccine appointment at an OPH community clinic,” Dr Bourns added.

The measles vaccine's effectiveness is bolstered when a majority of the population has it.

"Measles has a very, very effective vaccine but it does require large proportions of people to be vaccinated to achieve what we call herd immunity, which means that there is such a protection in the community that it ensure that babies or immunocompromised people who are not able to be vaccinated can still be protected by the protection that exists in the community," said Public Health Ontario physician Dr. Sarah Wilson.

Herd immunity requires an uptake of around 95 per cent, Wilson said.

"We have been very fortunate historically in Ontario, despite having at least a handful or more measles importations every year, that we’ve been very successful in not having large outbreaks. That’s really a testament to the uptake of measles vaccine."

While OPH administered approximately 25,000 catch-up doses of routine childhood immunizations to around 10,000 children and youth up to the age of 18 years through OPH’s community clinics, neighbourhood health and wellness hubs and school clinics in 2023, it has administered a total of 4,767 doses of routine childhood vaccines to 2,276 children and youth 0-18 years to date in 2024 – up to Feb. 14.

"I think people are a little bit tired of hearing about immunizations all the time, but it doesn't reflect the fact that immunizations for a variety of illnesses, measles particularly, are really important," said infectious disease physician Dr. Dale Kalina. "Measles is one of those first harbingers, or the canary in the coal mine if you will, of diseases of an under-immunized population. So, that is what we're starting to see.

"The reality is, the disease itself can be mild but it can also have very severe consequences and so it's dangerous to expose people to a virus that can be unpredictable. The safest thing to do by leaps and bounds, is to be vaccinated."

More information is available online.

With files from CTV News Ottawa's Ted Raymond and Austin Lee, CTV News Montreal's Daniel J. Rowe and CTV News Toronto's Katherine DeClerq