Canada loses its official ‘measles-free’ status – and the US will follow soon, as vaccination rates fall
In a significant public health setback, Canada has lost its measles-free status after a major outbreak in 2025, marking a stark reversal from its successful elimination of the disease in 1998. The Pan American Health Organization (PAHO) announced this decision on November 10, 2025, following a review of alarming public health data that revealed over 5,000 measles cases across the country. This outbreak has not only affected thousands, including infants and children, but has also resulted in tragic fatalities, including the deaths of two infants. The resurgence of measles in Canada is part of a troubling trend observed across North America, where both the United States and Mexico are experiencing significant outbreaks, raising serious concerns about declining vaccination rates and public trust in health initiatives.
The decline in vaccination rates has been particularly pronounced in Canada, where the percentage of two-year-olds receiving at least one dose of the measles vaccine plummeted from around 90% in 2019 to just 82% by 2022-2023. This drop in immunization has left many children vulnerable to measles, a highly contagious disease that can spread rapidly in populations with low vaccination coverage. The World Health Organization (WHO) emphasizes that maintaining vaccination rates of approximately 95% is crucial to prevent outbreaks. With only 10% of those infected in the recent outbreak having been vaccinated, the situation underscores the importance of addressing vaccine hesitancy and misinformation, particularly in the wake of the COVID-19 pandemic, which has exacerbated public skepticism towards vaccination efforts.
As Canada grapples with this public health crisis, the implications extend beyond its borders. The United States, which has also seen its highest number of measles cases since 1992, is likely to lose its measles-free designation in 2026, following a series of outbreaks that began in early 2025. Similarly, Mexico has reported thousands of cases, predominantly among unvaccinated individuals. The interconnected nature of global health means that outbreaks in North America pose a risk to other regions, potentially threatening the measles-free status of Central America, South America, and the Caribbean. Without immediate action to improve vaccination coverage and rebuild trust in public health messaging, the likelihood of future outbreaks of measles and other vaccine-preventable diseases looms large, necessitating a concerted effort to prioritize community health and safety.
Canada eliminated measles in 1998 but had a major outbreak in 2025.
jure/iStock via Getty Images Plus
In the wake of a
measles outbreak in Canada that has infected
thousands of people over the past year, an international health agency
revoked the country’s measles-free status
on Nov. 10, 2025.
The Pan American Health Organization, which serves as the World Health Organization’s regional office for the Americas, made this announcement after the agency’s
measles elimination commission
met in Mexico City to review the latest public health data.
As a
global health epidemiologist
who studies the spread of infectious diseases, this change in status does not surprise me. Measles is highly contagious, and a drop in childhood vaccination rates
in Canada
and in other countries has left many children unprotected from the disease.
The resurgence of measles in Canada after decades with very low numbers of cases
is not an isolated problem
. The U.S. has also had
large outbreaks of measles this year
, and it will likely soon lose its measles-free designation as well.
The loss of measles elimination status is a symptom of a deeper issue:
declining trust
in public messaging about science and health, which has led to decreased vaccination rates and growing vulnerability to vaccine-preventable diseases.
What does it mean for a country to be measles-free?
Measles is one of the most contagious diseases on the planet. Before the measles vaccine was
licensed for use in 1963
, nearly every child got measles infection and
more than 2 million children died
from measles each year.
The vaccine decreased that risk dramatically. By 1968, five years after the vaccine became available, case counts in the U.S. had
dropped by more than 95%
. Cases in Canada also
decreased substantially
after the vaccine was introduced.
Tragically,
about 100,000 children still die from measles
each year even though a safe, effective and low-cost vaccine is available. Almost all of those deaths occur in low-income countries where many children do not have access to recommended vaccines.
The World Health Organization uses
three labels to describe
how well a country is preventing the spread of infectious diseases such as measles. A disease is said to be controlled when public health interventions such as routine childhood vaccinations significantly lower the rate of new infections. A disease is considered to be eliminated from a country when the only cases that happen are small outbreaks linked to international travel. And finally, a disease is deemed eradicated only after several years of no cases occurring anywhere in the world.
To achieve the status of measles elimination, a country must have no ongoing local transmission of the disease
for at least one year
. It will lose that status if it has a chain of cases that spread from person to person for more than one year.
Measles cases have occurred in every province in Canada in 2025.
Once a country has eliminated measles, there is almost no risk from the disease as long as vaccination rates stay high. But when vaccination rates drop, outbreaks will soon start happening.
What happened in Canada?
In 1998, the Pan American Health Organization
confirmed that Canada had eliminated measles transmission
. Two years later, the U.S. also
gained the measles-free designation
.
By 2016, every country in the Americas had achieved measles elimination status. The region
lost that status in 2018
after outbreaks in Brazil and Venezuela, and then
regained it in 2024
.
But childhood vaccination rates
have been falling worldwide
, especially during and after the COVID-19 pandemic. To protect communities from measles outbreaks,
about 95% of the population
must be vaccinated against the disease.
In Canada, the percentage of 2-year-olds who have received at least one dose of measles vaccine dropped from about 90% in 2019 to
about 82% in 2022 and 2023
. As the number of unvaccinated people in the population increased, the risk of measles outbreaks grew.
After having only 16 total cases of measles nationwide between 2020 and 2023, the number of measles cases in Canada jumped to more than 100 in 2024 and
more than 5,000 cases in 2025
. Cases have occurred among infants, children and adults in every Canadian province in 2025, and two infants have died.
Fewer than 10% of the people who have gotten sick had been vaccinated against the disease.
What happens next?
It is likely that both the U.S. and Mexico will lose their measles-free designation in 2026, because both countries have had
sustained outbreaks of measles
since early 2025.
Although
more than 90% of kindergartners in the U.S.
are vaccinated against measles, that rate is too low to protect communities from outbreaks. An
outbreak that started in Texas
in January 2025
infected more than 760 people
and caused the deaths of two children.
In total, more than
1,600 Americans
in more than 40 states have gotten sick from measles in 2025. That is more cases than any year since 1992. More than 90% of the people who got sick were unvaccinated.
Mexico has also had
thousands of measles cases this year
, mostly among unvaccinated people.
Central America, South America and the Caribbean will retain their measles-free status for now. But the outbreaks in North America increase the risk of measles spreading to other countries.
Without a significant improvement in vaccination coverage and public trust in community health measures, many countries are likely to face more, and bigger, outbreaks of measles and other vaccine-preventable diseases in the coming years.
Kathryn H. Jacobsen does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
