Professor Stacey Smith? (the question mark is part of her name) specializes in infectious disease modelling using differential equations. Her research helps scientists and policymakers understand how diseases spread and how interventions, from vaccination campaigns to school closures, might shift an outbreak’s trajectory.
Mathematical models are especially useful in the early stages of a pandemic, when limited data makes real-time decision-making difficult.
“Models can be incredibly valuable, especially when there isn’t much data available. They can’t tell you exactly what will happen, but they can show best-case, worst-case and average scenarios. Decision-makers can then use that information to make informed choices,” Smith? explains.
Smith? saw the importance of these models first-hand during the earliest days of the COVID-19 pandemic. Over the course of one evening (March 12, 2020), she gathered data, generated projections and sent her findings to University of Ottawa leadership at 2 a.m. By 9 a.m., the University had announced it was moving classes online, days before government-mandated lockdowns began.
Besides COVID-19, Smith? has modelled everything from Ebola outbreaks to hypothetical zombie epidemics. Today, however, her attention has shifted to something less obvious but just as contagious: vaccine hesitancy.
When misinformation goes viral
In April 2026, Smith? took part in the Matrix Collaborative Workshop for Under-Represented Genders Advancing Mathematical Biology, held at the University of Melbourne in Australia. On top of hosting an equity, diversity and inclusion panel and a career workshop, she led a group investigating the spread of misinformation through anti-vax attitudes and vaccine hesitancy.
Together, the researchers developed a mathematical model describing three groups in today’s post-pandemic landscape: those who support vaccination, those who oppose it and those who remain vaccine-hesitant.
While inspired by COVID-19, the model extends far beyond a single virus. Declining uptake of routine childhood vaccines (including those for measles and hepatitis) has made understanding vaccine attitudes more important than ever.
“On social media, vaccine attitudes are very transmissible,” Smith? says. “If I'm very anti-vaccine and I convince you that getting a vaccine is a bad idea, then you’ll change your status. That’s very similar to getting infected by a disease. We have a contact, there’s an exchange of something and then you change state.”
Through their model, Smith? and her collaborators discovered that when a population contains a high number of people who are hesitant but not firmly opposed to vaccination, immunization rates can decline enough to create more waves of disease transmission.
“Mathematically, you get this strange effect in the middle where extra waves emerge that otherwise shouldn’t exist.”
Knowledge is power
In an online world increasingly shaped by misinformation and artificial intelligence, Smith? believes scientific literacy has never been more essential.
The workshop with Smith? during the Matrix conference fell on Women in Mathematics Day. For the occasion, The Random Sample podcast invited her to discuss her research, and she immediately accepted. Whether through podcasts, interviews or articles like this one, Smith? sees public engagement as a necessary extension of her work as a researcher.
When speaking with vaccine-hesitant people, Smith? approaches the conversation with empathy. She understands that science can feel intimidating. At the same time, she points to one undeniable reality: vaccines have dramatically improved human health and doubled the average life expectancy over the past century.
Rather than encouraging people to blindly accept information, Smith? urges them to ask questions and think critically. One of the most accessible and reliable places to start, she says, is by talking with a family doctor.
“It’s OK to update your beliefs as new information becomes available. That’s a sign of thoughtful reasoning rather than instinctive reaction.”
Knowledge can be contagious too, and unlike misinformation, it’s something worth spreading.