The Mathematics of Immunity

Vaccines are here and already in the arms of a great many Canadians. But accessibility still cannot be taken for granted. The ongoing demand for vaccines, including booster shots, has health officials worried that there might not be enough doses to go around.

Supply chain disruptions, exacerbated by the pandemic, continue to hamper vaccine delivery systems worldwide. It’s a pressing problem for which mathematician Suzan Farhang Sardroodi has found a workable solution.

Using mathematical modelling to investigate the dynamics of an immune response, she identifies a strategy for circumventing logistical constraints while safeguarding vaccines at a time of shortages.

“By halving or even quartering a second booster dose and extending the time between shots from the typically prescribed 16 weeks to as long as 18 or 20 weeks, vaccines that are in short supply can become available to anyone who wants them,” says Farhang Sardroodi, a senior postdoctoral fellow in the Modelling Infection and Immunity Lab at York University. “The shortened time period, combined with a smaller dose, is statistically proven to be just as effective in protecting people against infection.”

Marking the Iranian-born researcher’s first foray into infectious diseases (her previous investigations have centred on oncology), the three-month study is the focus of a paper recently published in the monthly international peer-reviewed journal Vaccines. The findings uncover a way to circumvent logistical constraints while keeping people safe in the pandemic. It’s math applied to a real-life problem, and for Farhang Sardroodi, who joined the University last fall, that’s what makes it exciting.

“Often students ask me how math can have meaning and now I can show them this, a mathematical model that has been able to simulate an immune response in the human body. It’s an encouraging development,” she says, “because it shows how math can truly make a difference.”  ■