Pictured: Dr. Michelle Barton-Forbes in her office.
March 19, 2025
Measles cases are rising across southwestern Ontario, and we sat down with Dr. Michelle Barton-Forbes, head of paediatric infectious diseases at Children’s Hospital at London Health Sciences Centre (LHSC), to talk about how you can keep your family safe.
What is measles and how does it spread?
Measles is a highly contagious viral infection. It spreads through the air when an infected person breathes, or through droplets when they cough or sneeze.
The virus can linger in the air for up to two hours, making it incredibly easy to catch if you’re not vaccinated. In fact, nine out of 10 unvaccinated people who are exposed will catch it. It’s the most contagious virus known to humans.
What are the common signs and symptoms and when do they appear?
Symptoms typically begin about seven to 21 days after a person is exposed. You are considered contagious at this point.
Initially, you might feel like you have a common cold. You're likely to experience a fever, sore throat, cough and runny nose. You may even have red, watery eyes like when a person has conjunctivitis (pink eye).
About three to seven days after your initial symptoms begin, a patchy rash will appear on your face and spread down the rest of your body. The rash appears red on light skin but can appear white or purple on dark skin. This can be challenging because people associate measles with a red rash, not necessarily a white or purple one.
That said, it’s important to note that not everyone will get the same symptoms – or any symptoms at all. To be clear, measles is NOT a cold with a rash.
Why is measles considered a dangerous disease?
Measles is dangerous because it can affect multiple areas of the body, from the lungs to the intestines and the brain. It can lead to severe complications, including death, during the infection or after.
The most common complication requiring hospitalization is pneumonia or respiratory failure, which may result in someone needing oxygen or a ventilator. Measles also commonly causes gastroenteritis (vomiting and diarrhea), leading to dehydration. Additionally, you can get meningitis (swelling of membranes surrounding your brain and spinal cord) and encephalitis (swelling of the brain itself), as well as damage to your immune system and permanent blindness.
For individuals who are pregnant, measles can affect the growth of baby and lead to a miscarriage, stillbirth or premature labour. The baby can also become infected.
In rare cases, unvaccinated children who contract measles will experience a special type of brain swelling that is associated with degenerative decline, sometimes resulting in a coma, 10 to 12 years after their initial infection has passed.
Thankfully, measles is entirely vaccine preventable. (More on that below.)
Who is most at risk for complications?
While the risk of complications from measles is low for healthy individuals, it can be particularly catastrophic for babies and young children, pregnant persons and those who are immunocompromised.
About one in 20 healthy people will experience complications from measles and one in five children will require hospitalization.
The mortality rate for measles is one to three people per 1,000 healthy individuals, 40 to 70 per cent for high-risk groups (such as those with cancer or those who have received a transplant) and three to 20 per cent for pregnant individuals.
Tell me about the measles vaccine. How does it work and is it safe?
The Measles, Mumps and Rubella (MMR) vaccine is our best protection against the virus. It’s given in two doses; the first around one year old and the second at four to six years old. If someone didn’t receive the vaccine as a child, they can still get it as an adult.
The vaccine works by introducing a weakened version of the virus to your immune system so it can create antibodies. These antibodies are what helps your body recognize and fight off the actual virus when you’re exposed to it in the real world.
The measles vaccine is safe and highly effective (about 97 per cent). Like with other vaccines, you may have minor side effects such as a sore arm or redness after receiving it, but these are not serious and resolve quickly. Contrary to what you might have read online, the vaccine does not cause autism.
Anyone who has questions about their immunity status or would like to receive the vaccine is encouraged to contact their primary care provider or local health unit. After receiving both doses of the vaccine, it will take about two weeks before you are considered immune.
I thought measles was eradicated. Why are cases rising now?
While measles was eradicated in Canada in the 90s, it continued to circulate in other parts of the world that didn’t have such high vaccination rates.
Unfortunately, in recent years, we’ve seen a drop in vaccine rates across Canada. This is partially due to the health-care system playing catch up after the COVID-19 pandemic, but also because of rising vaccine hesitancy being fueled by misinformation online. Some communities are also less willing to vaccinate because of cultural or religious reasons.
So, measles is once again circulating across Canada – and perhaps the fastest across southwestern Ontario. It’s like a fire that will burn until it runs out of trees. Practically speaking, this means until 95 per cent of the population is vaccinated and we’ve once again achieved herd immunity.
While new cases are being announced every day, they are likely significantly underestimated, as not everyone who gets the virus seeks care. We would likely have to multiply current cases by four to 10 to have an accurate picture of the number of people in Canada who are currently infected with measles.
How is measles treated?
There is no specific treatment or antiviral for measles. This means that once an infection occurs, care providers focus on relieving a patient’s symptoms and preventing complications while their body fights the infection.
What is Children’s Hospital and the rest of London Health Sciences Centre doing to keep patients safe from measles?
As a tertiary acute care centre with a catchment area reaching as far north as Thunder Bay, many of our patients are considered high-risk for measles complications. This is why we’ve recently announced care partner and visitor restrictions to keep our most vulnerable patients safe.
This new policy – which is being re-assessed weekly by our teams in areas like Infection Prevention and Control, Risk, Privacy, Ethics and Patient Experience – requires people to pass screening and provide proof of immunity. Masking requirements take into consideration whether the visitor can prove immunity and whether they are entering an area where patients with weak immune systems may be present. It is effective until further notice at Children’s Hospital and in the Women’s Care program.
LHSC’s Infection Prevention and Control team has also developed internal policies and procedures aimed at preventing and controlling the spread of measles within the hospital environment – and we strictly adhere to these. For example, all LHSC staff are required to provide proof of measles immunity. Frontline teams must also mask when providing direct patient care and are responsible for enhanced patient screening, testing to confirm a patient’s infection or immunity, and placing patients with a suspected or confirmed case in negative pressure rooms. Patient transport pathways have also been redesigned to minimize potential exposure when someone with measles must be moved from one part of the building to another.
In addition to that, LHSC is working alongside our public health partners to vaccinate as many people as possible. Adults and children who are interested in getting the measles vaccine are encouraged to contact their primary care provider or local health unit; however, we are home to a special Paediatric Vaccination Clinic for children and youth who need extra support not typically available in traditional health-care or community vaccination settings. Our paediatric infectious diseases team also runs a vaccine hesitancy clinic that offers support to patients and families who are unsure about getting vaccinated.
Furthermore, we’re offering virtual care options for eligible patients who wish to avoid coming into the hospital because they’re immunocompromised, may have been exposed to the virus or have symptoms. This helps ensure all patients receive the care they need without putting others at risk.
How is the paediatric infectious diseases team contributing to the response?
The paediatric infectious diseases team is involved in the care of patients admitted to Children’s Hospital with suspected or confirmed cases of measles. All but one of the patients we’ve seen so far have been unvaccinated, and while some were immunocompromised, others were previously considered healthy. This underscores the importance of receiving the MMR vaccine even if you don’t currently have any current health issues.
We are also providing ongoing consultations to regional hospitals who are caring for patients with measles in their area. This allows those patients to remain closer to home while still benefiting from the expertise of our paediatric infectious diseases team.
Where can I find more trustworthy information about measles?
Anyone who would like more information about measles is encouraged to reach out to their primary care provider or local health unit. The Middlesex-London Health Unit and Southwestern Public Health Unit, for example, have some excellent resources online, as does the Canadian Paediatric Society’s Caring for Kids initiative.