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Sainte-Justine Hospital in Montreal on Feb. 8, 2023.Graham Hughes/The Canadian Press

Ten cases of measles have been confirmed in Greater Montreal over the past few weeks, making the city the epicentre of the current Canadian outbreak, Quebec health officials said Monday.

Caroline Quach-Thanh, a pediatrician, microbiologist and infectious disease specialist at CHU Sainte-Justine in Montreal, said seven of the cases appear to have been acquired locally, while the rest were connected to international travel. The latest case was identified Sunday, she said during a news conference.

More than a dozen measles cases have been reported in Canada recently. One was confirmed last week in the York region of the Greater Toronto Area. Another was found in a Brantford-area child who returned from Europe.

One more case was reported in British Columbia over the weekend, where officials advised people on Monday to get vaccinated before travelling during the coming spring break.

Only 12 cases of measles were reported in Canada in all of 2023.

“We are concerned about the situation,” said Quebec Public Health Director Luc Boileau, who warned that the disease could spread rapidly among unvaccinated people. “Public health is following the evolution of all these situations very closely.”

Last month, the country’s Chief Public Health Officer, Theresa Tam, issued a statement in advance of March break saying she is concerned that an uptick in measles cases around the world could lead to transmission of the virus in Canadian communities with low vaccination rates.

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For now, Quebec does not intend to make vaccination mandatory, Dr. Boileau said, but rather will provide information, facilitate access to shots and answer people’s questions.

“The vaccine is safe, it’s efficient, it acts quickly, it’s the best way to protect oneself from measles.”

Montreal public health director Mylène Drouin said seven of the province’s 10 cases occurred in the city. Places and times where contact with identified infected people could have happened were posted on the Montreal Health website, along with tips on what to do if you were exposed or show symptoms.

Vaccination coverage is too low in schools in Montreal and its suburbs, such as Laval and cities in the Montérégie region, and in Quebec City, Dr. Boileau said, adding that unvaccinated children will have to be pulled from class in the case of an outbreak.

A vaccination rate of 95 per cent is required to prevent community transmission. In Montreal schools coverage averages about 80 per cent, Dr. Drouin said. Some schools have rates as low as 30 per cent, though this could partly be the result of delays in translating foreign vaccination records, she added.

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Vaccine hesitancy and limited access to vaccines for newly arrived children play a role, Dr. Drouin said. Local health authorities will organize vaccination campaigns in schools where coverage is particularly low and will also contact individuals directly to answer questions and facilitate appointments.

Dr. Quach-Thanh said that although the rash that typically presents with measles looks benign, several complications can occur, including ones with debilitating or potentially fatal outcomes. Ten per cent of infected children develop pneumonia, some of whom need hospitalization, she said.

Between one in 1,000 and one in 600 children can develop complications such as encephalitis (inflammation of the brain), measles-induced acute disseminated encephalomyelitis (swelling in the brain and spinal cord) or subacute sclerosing panencephalitis (which affects the central nervous system).

“One out of 3,000 might die,” Dr. Quach-Thanh said.

The World Health Organization reported a 79 per cent increase in the number of global measles cases in 2023 compared with the previous year.

Quebec public health authorities said on March 4 that measles is now spreading in the Montreal area, where 10 cases of the virus have now been detected.

The Canadian Press

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