Ontario's first measles death in decades is a somber reminder that unvaccinated children are at risk

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The measles deaths of children in Ontario this year are a stark reminder that when vaccination rates decline and this virus rages on, the youngest among us will bear the brunt. .

Public Health Ontario (PHO) recently reported the death of a child under the age of five. on thursday. The child from Hamilton, Ont., is one of five unvaccinated children to be hospitalized this year, for a total of 22 measles cases reported in the province.

That means in just a few months in 2024, Ontario saw nearly a quarter of the nearly 100 measles cases recorded over the previous decade. The PHO said this year's death was the first in the state since 1989, going back to data.

Dr. Alison McGeer, a leading infectious disease expert, called this tragic but not surprising.

“This is something that people have spent a lot of time and effort trying to avoid,” added McGeer, who works at Toronto's Sinai Health System. “There is an aspect of it that is inevitable because of how much ground we have lost with measles vaccination around the world.”

World wide, and in canada, In recent years, vaccination rates for various infectious diseases have been declining. This is giving measles, once considered a disease of the past, a chance to come back with full force.

In Ontario, for example, between the 2019-2020 season and 2022-2023, the proportion of seven-year-olds with zero vaccinations increased dramatically from less than 4 per cent to nearly 17 per cent. The March PHO report states:.

“Many people may not have been able to receive the vaccine during the dark days of the pandemic, when several public health programs were curtailed due to the enormous impact of the pandemic,” said Isaac, an infectious disease expert at the University of Health.・Dr. Bogoch said. Communication network.

It's a similar scene in other places.Measles cases are increasing rapidly this year in Montreal and other parts of Quebec; Infection in the United States Already reached the highest level since 2019; and outbreaks continue to occur around the world; Including an ongoing cluster of infections in London, UK

As PHO pointed out in its latest report, people traveling to and from hotspots also mean the virus is traveling around the world on a daily basis, accounting for 15 of the state's recent cases. are directly related to international travel.

It's also highly contagious, meaning measles can linger in the air for hours. And one infected person can spread the infection to 9 out of 10 unprotected people around them..

Who is most at risk? Several medical experts highlighted children who have not yet been vaccinated.

Vaccine efficacy remains high

“If you look at the data in any state, the problem is children who are not being vaccinated,” McGeer said.

That's because measles is a one-time infection. Once you are infected with the virus, you are protected for life from serious infections. This means that most older people have immunity through prior infection, vaccination, or both.

Babies and young children, on the other hand, are often extremely vulnerable, especially if they are too young for their first vaccination.

“If a mother has immunity to measles, that immunity will be passed on to her baby,” said Dr. Donald Bing, an infectious disease expert at McGill University. “But it's not forever.”

Canadian children typically receive their first dose of the measles-mumps-rubella vaccine at 12 to 15 months of age, so there is a period when infants may be unprotected.

But just one shot is thought to be more than 85 percent effective. Federal numbers suggest, while the efficacy level of the complete dose set is almost 100 percent. Many experts also recommend that infants traveling abroad receive a booster shot earlier than 12 months of age, in which case they should receive a series of three shots.

As overall vaccination rates decline, unvaccinated children could easily become infected with this highly contagious virus, said Dr. Caroline Quack-Tan, a pediatrician and professor at the University of Montreal. Emphasize.

In some cases, it may be the result of parents choosing to avoid vaccinating their children. However, Kwak Tan pointed out that children with weakened immune systems, including those undergoing chemotherapy, cannot receive the measles vaccine. Measles vaccines contain a weakened version of the virus, making them highly effective for the general population, but dangerous for people with weakened immune systems. immune system.

“So if you vaccinate them, it could lead to measles because their immune system is too weak to control the vaccine,” Kwaku Tan explained.

Serious health consequences for unvaccinated children

If unprotected infants and children become infected with measles, symptoms are often mild. But beyond the obvious rash, there can be far-reaching health effects.

Kwak Tan said measles is thought to be fatal in 1 in 3,000 cases.Also known as cause other life-altering illnesses Pneumonia, brain inflammation, hearing loss, etc.

He also spoke about research suggesting that devastating health problems can occur years after the initial infection, including a condition known as subacute sclerosing panencephalitis (SSPE) or Dawson's disease. also pointed out. Progressive neuropathy is persistent, disabling, and ultimately fatal.

In a study by researchers in California, Published in the medical journal “Clinical infection infection” in 2017showed that the incidence of Dawson's disease was higher among unvaccinated children, especially those infected with measles in infancy.

“SSPE indicates that 'natural' immunity to measles has a high cost to humans,” the researchers wrote.

Quebec's efforts to curb measles outbreak

Experts agree that higher immunization levels are needed to limit these health effects. And this year, Quebec proved that progress is possible.

Despite some leeway in vaccination rates in schools. approximately 30% lowerThe state has been able to contain the surge through contact tracing efforts, post-exposure vaccinations of high-risk contacts, and what Kwaktan calls “aggressive” efforts to improve school vaccination rates.

The strategy appears to be working, as the number of cases has remained largely stable, with a total of 51 cases so far this year, including almost half of Montreal's cases. .

And thankfully there were no fatalities.

“We were lucky,” Kwaku Tan said. “It could have happened to us too.”