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The Founding College of the University of Toronto

Early Women Scientists


How two UC alumnae helped beat infectious disease

By Dan Falk

            For older Canadians, the current coronavirus pandemic may seem eerily familiar. As recently as the 1950s, the nation was gripped by a series of polio outbreaks, a terrifying disease that caused paralysis, disability, and death. The disease, nicknamed “the crippler,” infected 50,000 children and left 4,000 dead. It also left health care professionals and scientists scrambling to find a treatment. In fact, there were many parallels between the battle against polio and today’s fight against COVID-19, including school closures and restrictions on cross-border travel. Eventually, a vaccine was successfully developed – and while the American scientist Jonas Salk became a household name, a number of Canadian women scientists, including two UC alumni who worked at the Connaught Laboratories in Toronto, also played a vital role in ending the polio scourge.

            Among those nearly forgotten polio fighters was Dr. Leone N. Farrell (BA 1928 UC). Born in Monkland, a small town in eastern Ontario, Farrell moved to Toronto with her family and remained there until she completed her master’s at the University of Toronto in 1929, working on the chemistry of fermentation. She continued her studies in Ottawa and in London, England, before returning to Toronto, completing her doctorate at U of T in 1932. She joined Connaught the following year.

            Farrell’s work focused on the development of toxoid vaccines used against staphylococcus and dysentery. (Toxoid vaccines use a toxin created by the same germ that causes the disease itself; the idea is to create immunity to the specific parts of the germ that cause the disease, creating a more targeted immune response.) While working on these toxoid vaccines, Farrell came up with a new technique in which specially designed machines were used to gently rock cell cultures back and forth, which accelerated the production of the vaccine material. Later, she would employ this technique, which came to be known as the Toronto method, in the effort to produce a polio vaccine.

            Salk’s breakthrough involved taking the live polio virus and killing it with formaldehyde. When injected into patients, this dead material triggered the body to produce antibodies to fight the disease, providing immunity. But he was only able to create small amounts of the virus at a time, using kidney cells from monkeys and cultivating them in test tubes. However, researchers at Connaught developed a technique for growing a synthetic version of the virus with similar properties, known as Medium 199. The material was packed in ice and shipped from Toronto to Salk’s lab at the University of Pittsburgh.

            Salk’s method worked, but it was a struggle to keep up with demand – just as we’re seeing today in the fight against COVID-19. It was Farrell’s rocking technique that allowed larger quantities of the vaccine to be made quickly. Farrell oversaw the hiring of additional staff and the construction of more machinery to speed up production of the vaccine. The work involved contact with monkeys and Farrell recognized that it was dangerous; her thoughts are preserved in notes now housed in the Sanofi Pasteur Canada Archives. “That no infection occurred at the time seems miraculous in retrospect,” she wrote. “I believe everyone thought at least once that they had contracted the disease.”

            Anxious to see a vaccine available for Canadian children, the federal government approved the Salk vaccine even as clinical testing – carried out in Canada, the US, and Finland – continued. Ultimately, the vaccine was shown to be highly effective. By the summer of 1956, Connaught had produced enough polio virus to make 2.3 million doses of the vaccine.

            Farrell received little public recognition in her lifetime. In the 1950s, Salk – who did appreciate the significance of Farrell’s work – visited Toronto with the aim of meeting Farrell and thanking her in person. But things did not go well. A ceremony in Salk’s honour was held in the dining room of U of T’s School of Hygiene where, at the time, only men were admitted. Female scientists who wanted to speak with Salk were told they could stand by the doorway; Farrell declined. Grace Darling, who worked with Farrell in the 1960s, told the Toronto Star that Farrell felt “that she didn’t get the recognition that she should have because she was a woman and not a man.”

            Farrell retired in 1969 and died in 1986. She is buried in an unmarked grave. Much later, in 2009, her name and a tribute to her work were added to a family gravestone. Christopher Rutty, a medical historian and adjunct professor at U of T’s Dalla Lana School of Public Health, has described Farrell as a “unique person” who played a key role in the fight against infectious disease. “Without her, there really wouldn’t have been a [polio] vaccine, at least not then,” he told the New York Times recently.

            Farrell was not alone. Dr. Edith Marjory Taylor (BA 1921 UC), an immunologist who earned a doctorate in chemistry from U of T in 1924, played an important role in the fight against diphtheria. Born in 1899 into a Toronto family of ten children, Taylor joined Connaught in 1925. There, she worked alongside Peter J. Maloney in developing a more highly purified diphtheria toxin. She continued this work through the Second World War and helped develop toxins against tetanus and gangrene – both of which posed a severe threat to soldiers on the battlefield. Her work led to an improved tetanus toxoid which was both highly effective and free from detrimental side effects. Later, Taylor was involved in testing the Salk polio vaccine. An article in the Globe and Mail in 1945 noted the success of the tetanus toxoid in treating members of the Canadian Armed Forces. During the First World War, tetanus afflicted 32 out of every 1,000 allied soldiers; in the Second World War, the article noted, tetanus was “practically non-existent among Allied troops because of immunization.” After the war, Taylor was awarded the Order of the British Empire for her medical research.

Dan Falk (@danfalk) is a science journalist based in Toronto. His books include The Science of Shakespeare and In Search of Time.