Measles was once nearly wiped out in North America. Now it’s making a comeback, spreading fast and dragging dangerous misinformation along with it. 

From October 18, 2024, to March 26, 2025, Ontario has reported 572 cases of measles. Last month, the US reported its first measles-related death since 2015. An unvaccinated child died during a measles outbreak in Texas that had infected over 120 people. Health officials confirmed the death and warned that such outcomes are entirely preventable with routine vaccination. 

This was a tragic example of how misinformation can lead to preventable outcomes.

From parents hosting “measles parties” to US Secretary of Health and Human Services and vaccine conspiracy theorist Robert F. Kennedy Jr. downplaying the recent outbreak as “not unusual,” a flurry of controversies has arisen over vaccine safety. 

Why measles spreads like wildfire

Measles is an incredibly contagious disease caused by the measles virus (MeV). It’s a viral infection that mainly affects the respiratory system, causing fever, red skin rashes, coughing, and conjunctivitis, also known as pink eye. Measles can also suppress the immune system, making individuals more susceptible to other infections. In severe cases, the virus infects the lungs and causes pneumonia, a severe lung infection. Rarely, measles can cause encephalitis, which is the inflammation of the brain tissue.

If someone has the virus and breathes near an unvaccinated person, there’s a 90 per cent chance they’ll catch measles​. On average, a person infected with measles can spread it to 12-18 others. For comparison, the flu has a spread rate of about one or two people, while early in the pandemic, COVID-19 had a spread rate of about two to three.  

In the US, about one in five unvaccinated people who get measles end up in the hospital. Among every 1000 infected children, one to three die from pneumonia or associated neurologic complications​. Even years after recovering, measles can still be deadly. 

A rare and fatal brain disease called subacute sclerosing panencephalitis (SSPE) can develop several years later in a person who recovered from measles. SSPE mostly affects children who contract the virus. Their underdeveloped immune systems can allow the measles virus to eventually invade the central nervous system and cause epilepsy, speech regression, and vision loss. 

Measles’ reappearance in communities across Canada and the US is raising alarms among health professionals, especially as vaccination rates decline and immunity wanes.

Why is measles back? Declining vaccination rates and measles parties

Archchun Ariyarajah — a PhD candidate in epidemiology at the Dalla Lana School of Public Health — and Associate Professor Shelly Bolotin, who is researching waning measles immunity in Ontario, wrote to The Varsity in an email to help us understand why measles is coming back. 

“The rise in measles cases is due to several factors,” Ariyarajah wrote. “Firstly, there have been barriers to accessing vaccination. The lockdowns during the COVID-19 pandemic disrupted childhood vaccination programs, causing vaccination rates to drop.” Missing out on key vaccination dates can be detrimental for infectious disease containment. 

He also pointed out that measles vaccination rates have been declining for years. “This is partly because vaccines have been so effective that many people have never seen a measles case in their lifetime and therefore, no longer see it as a threat.”

Ariyarajah and Bolotin went on to explain that the lack of visible cases, leading to the belief that measles is a non-issue, has led to parents skipping their child’s vaccines. The increase in uneducated online perspectives on the measles virus has contributed to a lower vaccination rate and higher numbers of people vulnerable to measles. 

Until the late 1990s, eliminating measles seemed within reach thanks to the development of effective vaccines, including the combined measles, mumps, and rubella (MMR) vaccine. Ariyarajah and Bolotin shared that prior to the vaccine, Canada saw 50,000 cases of measles per year alongside hundreds of deaths. Vaccination keeps these numbers from happening today.

While this should have led to positive outcomes in vaccine research, false claims about the MMR vaccine causing autism began to spread mostly through a single study that was published in The Lancet in 1998 and retracted in 2010 for falsified information. The study’s claims have since been completely debunked by further scientific research, but its damage remains. 

Some parents think it’s safer for their kids to catch measles ‘naturally’ by exposing them to the virus on purpose, hoping they’ll build up immunity. That’s the purpose of measles parties, where parents bring their children into contact with an infected person — ˇa terrible idea! 

During the 2018–2019 measles outbreak in New York City, there were 649 confirmed cases. Nearly 42.8 per cent of the cases were children aged one to four, and 15.6 per cent were infants under one, who were too young to be vaccinated. Researchers found that a spike in infections followed increased contact between young children, possibly due to these parties. Without this rise in contact, the outbreak could have been four times smaller. 

“Nearly three-quarters of measles cases in Canada during the recent outbreak occurred in people who were never vaccinated. This is the main driver of the outbreak, and it is particularly dangerous when individuals who are not vaccinated congregate together,” wrote Ariyarajah and Bolotin. 

Measles on campus? It’s a real risk

Universities also have to contend with measles outbreaks. With thousands of students living, studying, and socializing in close quarters, one case can quickly spiral.

“Measles is extremely contagious — it can linger in the air for up to two hours after an infected person leaves a room,” wrote Ariyarajah and Bolotin. “This means someone could walk into a room after the infected person has left and still get infected. Since measles spreads so easily, measles outbreaks are hard to control.

The good news? Measles is entirely preventable, and U of T students have access to free resources to stay protected. Students can book free vaccinations for diphtheria, polio, tetanus, mumps, measles, rubella, and others through Health & Wellness Services, which are available on all three campuses. 

Additionally, students planning international travel can access travel health clinics in Toronto for vaccinations. Campus nurses and doctors are also available to offer guidance on whether a booster shot or a blood test to confirm immunity is needed.

To protect against measles, it’s crucial for students to take proactive steps. Ariyarajah and Bolotin emphasize, “I encourage all students to check their vaccination records to make sure they’ve received two doses of the measles vaccine. […] Even if you have already been vaccinated, it is perfectly safe to be vaccinated again.” 

With accessible resources at U of T, students can easily ensure they are fully protected against measles and other vaccine-preventable diseases.