The Measles Resurgence in Canada: A Troubling Trend

The Rise of Measles Cases

Measles, a virus once thought to be nearly eradicated in Canada, is making an alarming comeback. As of February 21, 2025, Canada reported 95 cases of measles, a stark contrast to the four cases reported at the same time the previous year. This surge in cases is particularly concerning in British Columbia, Manitoba, Ontario, and Quebec, where the outbreak is most pronounced.

The Public Health Agency of Canada (PHAC) reports that by the end of 2024, the country had recorded a total of 146 cases. However, there has been an equally troubling trend in 2025. By the end of February 2025, almost the same number of cases were reported in Ontario as in the entire 2024. This data underscores a worrisome trajectory.

Unlocking the Contagious Nature of Measles

Measles is notoriously contagious, spreading rapidly through airborne particles when an infected person breathes, talks, coughs, or sneezes. The virus can linger in the air or on surfaces for up to two hours, making it highly transmissible. Dr. Isaac Bogoch, an infectious diseases specialist at Toronto General Hospital, noted, “If someone was in a room that had measles, and then an unvaccinated person enters, the risk of getting infected is high.”

With a reproductive number (R0) estimated at 12-18, measles is more contagious than COVID-19, influenza, and chickenpox. This high level of contagiousness, combined with areas of low vaccination rates, creates a perfect storm for outbreaks.

Did you know?

The Impact of Global Resurgence

The resurgence of measles cases worldwide has contributed to the influx of the virus into Canada, primarily through under- or unvaccinated travelers. Dr. Bogoch highlighted, “We’re living in the most mobile time in human history, so cases of measles are being imported into Canada almost inevitably.”

The Devastating Effects

Measles can lead to severe complications, such as pneumonia, brain swelling, permanent hearing loss, and in the worst cases, death, particularly in young children and those with weakened immune systems. Even in mild cases, the illness is extremely unpleasant. Dr. Theresa Tam, chief public health officer of PHAC, described the symptoms, highlighting the high fever, red eyes, and the classic rash that spreads from the face down the body.

On average, one in five children with measles requires hospitalization, a stark reminder of its severity.

Who’s at Risk?

Data from PHAC shows that 78% of those infected this year were unvaccinated, with the majority of cases occurring in individuals aged 5 to 17 (45%), followed by those aged 18 to 54 (26%). Children aged 1 to 4 accounted for 17% of the cases.

The Vaccination Challenge

The decline in measles vaccination rates across Canada has left an increasing number of individuals vulnerable to infection, weakening community immunity in the process. According to a study published in the Canadian Journal of Public Health, vaccination rates for the measles, mumps, and rubella (MMR) vaccine have dropped significantly, with coverage for one dose of MMR falling from 89.5% to 82.5% in 2023 compared to 2019.

This drop in vaccination rates, which accelerated during the COVID-19 pandemic, has fueled misinformation, leading to a backslide in public health progress.

Why Vaccination Matters

Pro tips
The measles vaccine, available as the MMR (measles, mumps, and rubella) or the MMRV (measles, mumps, rubella, and varicella), is highly effective. With one dose, efficacy is between 85% and 95%, and with a second dose, it reaches nearly 100%. The vaccine’s efficacy has led to a more than 99% decrease in measles cases since its approval in 1963.

October 2024 also highlights an Ontario outbreak sentenced further strengthening The message that: outbreaks can be challenging to control because the virus can spread before symptoms appear and remain on surfaces.
If someone does not get measles vaccination, one dose can be taken at 12 months, although eight doses to be given later to protect against illness due to waning immunity

Continuous Surveillance

Canada’s near-elimination of measles in 1998 resulted from extensive immunization campaigns. However, recent years have seen a steady rise in cases, mainly from international travel. For effective containment of outbreaks, especially in regions with pockets of unvaccinated individuals, continuous surveillance and vaccination are necessary.

<img src: "https://thewalterscale.com/wp-content/u ponloads/various-types-of-measles-and-loading-larger-scaled.jpg"; alt = "different era of occurrences">

FAQ: Measles and Vaccination

What are the most common complications from measles?

Measles can lead to serious complications, including pneumonia, brain swelling, permanent hearing loss, and even death, especially in young children and those with weakened immune systems.

. How effective is the measles vaccine?

The measles vaccine has shown to be 85% to 95% effective with one dose and nearly 100% effective with a second dose.

Q- How does measles spread? Q. Measles is one of the most contagious viruses and is easily spread via the air when an infected person breathes, talks, coughs, or sneezes. The virus can remain infectious on surfaces for up to two hours.

Who is most at risk for measles?

Individuals who are unvaccinated or under-vaccinated, especially children, are most at risk. The virus is also more dangerous for those with weakened immune systems.

Measles outbreaks pose a significant health threat, particularly in areas with low vaccination rates. Staying informed and encouraging vaccination can help prevent the spread of this highly contagious disease. Keep engaging with us for more health news and insights. Do not hesitate to notify or make comments? Let us know if you have any experiences with measles or vaccination concerns.