Why has Canada lost its measles-free status – and could the US be next?

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After nearly 30 years, Canada has lost its measles “elimination” status, which, by default, has caused the overall Americas region to lose its status as well.

In a statement issued on Monday, the country’s Public Health Agency stated that Canada was experiencing a “large, multi-jurisdictional outbreak of measles” which began in October last year.

What is measles?

It is a highly infectious virus which can be life-threatening if not caught early.

The illness, which is spread through the air when an infected person coughs or sneezes, begins with cold-like symptoms, including a runny nose, high temperature and sore, red eyes.

A few days after infection, small white spots can appear inside the cheeks and on the back of the lips. A rash then begins on the face and behind the ears before spreading across the body – the main telltale sign of the illness, according to information from NHS England.

In the worst-case scenario, measles can cause pneumonia and become life-threatening. Babies and anyone with a weakened immune system are most at risk.

Measles is widely prevented through the use of the MMR (measles, mumps and rubella) vaccine, which is administered in two doses to children at one year old and three years old.

According to the US Centres for Disease Control and Prevention (CDC), two doses of the vaccine are 97 percent effective in preventing a measles infection.

Why has Canada lost its measles status?

The “elimination” designation, which Canada has had since 1998, indicates that no locally transmitted infections or outbreaks have been reported in the past 12 months. This is no longer the case.

Mark Joffe, Alberta’s chief medical officer until earlier this year, blamed low take-up of vaccinations and told the Reuters news agency last month that more could have been done in the country to boost immunisation rates.

“If the vaccination rates were high, this would never have happened. There may have been [some spread], but nothing like this,” Joffe said.

Why are vaccination rates falling?

According to the WHO and the US CDC, the main reason measles is spreading is that fewer people are taking up vaccines across the Americas region generally.

One contributing factor for low vaccination rates is a growing distrust of healthcare providers following the COVID-19 pandemic, in which anti-vaccine misinformation spread.

One of the most persistent myths driving MMR vaccine hesitancy is the claim that it causes autism. This belief stems from a 1998 study, which has since been discredited and retracted. There is no scientific evidence of any link between the MMR vaccine and autism.

In some US states and Canadian provinces, exemptions for vaccine mandates – giving non-medical reasons for declining vaccines, such as for personal or religious reasons – are becoming more common. This has led to the existence of clusters of unvaccinated people who are more vulnerable to outbreaks when exposed to the virus.

Some communities, such as the Mennonites – Anabaptist Christians who have communities in the US, Canada and Mexico – have low vaccination rates, as conservative branches of the community do not believe in modern medicine. Several outbreaks in the past year have been traced to Mennonite communities.

Overall in Canada, according to public health data, measles immunisation also fell during the onset of the COVID-19 pandemic, when lockdowns made it harder to access general healthcare, and continued afterwards.

In 2019, 89.5 percent of children in Canada received their first dose of the MMR vaccine. But by 2023, that figure had dropped to 82.5 percent.

In the US, during the 2024-2025 school year, 92.7 percent of children received the vaccine, according to the CDC.

In Mexico, according to WHO figures, 79.86 percent of children received the first dose of the MMR vaccine.

At least 95 percent of a population is required to be vaccinated in order to achieve “herd immunity” against measles. Herd immunity means enough people have been vaccinated to make it too hard for the disease to spread.

Experts say the safest way to maintain herd immunity is through vaccination programmes.

How effective is the measles vaccine?

According to the World Health Organization (WHO), measles vaccination prevented an estimated 31.7 million deaths globally between 2000 and 2020.

The MMR vaccine, widely used around the world, provides about 97 percent protection against the measles virus, according to public health agencies.

The vaccine is normally given to children in two stages: The first dose at 12 months and the second at about three years and four months of age (when the child is nearing pre-school age), as part of routine immunisation programmes in countries like the United Kingdom.

Breakthrough cases in vaccinated people are rare and usually mild.

How has the wider Americas region been affected?

According to the Pan American Health Organisation (PAHO), part of the wider World Health Organization, Canada’s loss of its status means that “the Region of the Americas has lost its verification as free from endemic measles transmission”.

Once the MMR vaccine was approved for distribution in 1963, healthcare practitioners and school programmes were initiated in Canada, pushing for families to receive immunisation.

By 1998, Canada had achieved its measles elimination status. Two years later, the US achieved its elimination status, as well.

By 2016, the Americas region was declared free from measles, which meant that every country in the region had reached elimination status.

Following an outbreak in Venezuela and Brazil in 2018, the Americas lost its regional elimination status, only to have it reinstated last year once the outbreak was brought under control.

Now, the Americas region has lost its elimination status once again because of the Canadian outbreak. While many individual countries within the region still have their elimination status, measles cases are on the rise, generally.

As of November 7, the PAHO said, there were 12,596 cases of measles across the region, with about 95 percent reported in Canada, Mexico and the United States.

The PAHO said this was a “30-fold increase compared to 2024″.

Twenty-eight deaths have been recorded: 23 in Mexico, three in the United States, and two in Canada.

Jarbas Barbosa, director of PAHO, said the region’s loss of its elimination status was a “setback – but it is also reversible”.

“Until measles is eliminated worldwide, our region will continue to face the risk of reintroduction and spread of the virus among unvaccinated or under-vaccinated populations. However, as we have demonstrated before, with political commitment, regional cooperation, and sustained vaccination, the region can once again interrupt transmission and reclaim this collective achievement,” Barbosa said.

Which other countries in the region are at risk of losing their elimination status?

Currently, active outbreaks are occurring in Mexico, the US, Bolivia, Brazil, Paraguay and Belize, which have been “mostly triggered by imported cases”, according to PAHO.

Mexico

Mexico had reported 5,019 measles cases by October 31, according to data from PAHO. The cases are concentrated in the northern state of Chihuahua.

Just seven cases were reported in the whole of Mexico last year. A 31-year-old unvaccinated man from Ascension, Chihuahua, died from the disease in early April this year and at least 14 deaths have been reported since then, according to PAHO.

US

In the US, since January, a measles outbreak has led to 1,681 confirmed cases, according to the CDC last week.

In February, it reported its first measles death in a decade after an unvaccinated child fell ill amid an outbreak in Texas. The school-aged child died overnight after being hospitalised in Lubbock, northwest Texas, the state’s health department said.

Of those who have tested positive for the disease, 92 percent were unvaccinated or had unknown vaccination status.

Demetre Daskalakis, a former CDC official, told Reuters that the US has a deadline of January 20 to prove that it has curbed the outbreak if it is to retain its elimination status.

Are measles cases on the rise in other parts of the world?

Yes. In late 2023 and early 2024, there was a surge in measles cases in the UK, particularly in England.

In 2024 as a whole, there were 2,911 laboratory-confirmed measles cases in England, the highest number of cases recorded in a year, since 2012, according to the UK Health Security Agency.

In comparison, there were only two confirmed cases of measles across the whole of the UK in 2021 and 54 one year later.

There was another surge in cases in April 2025 – particularly in London and the northwest of the country – the agency said, but cases have since been declining. In 2025 so far, there have been 811 confirmed measles cases in England.

Western Australia, where 54 cases of measles have been recorded since the start of this year, is currently experiencing its worst outbreak of measles since 1997, according to Australian media.

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