https://quillette.com/2021/10/29/it-works-it-works-it-works-jonas-salk-and-the-vaccine-that-conquered-polio/
Excerpted, with permission, from You Bet Your Life: From Blood Transfusions to Mass Vaccination, The Long and Risky History of Medical Innovation, by Paul A. Offit.
Jonas Salk was born on October 28th, 1914, in a tenement in East Harlem, New York—the first son of Russian immigrants and the eldest of three brothers. After finishing four years of high school in three, Salk entered the City College of New York and later won a scholarship to the medical school at New York University. In December 1941, after the United States entered World War II, Salk was given a choice. He could either be commissioned as a doctor in the armed forces or remain in the United States to pursue a scientific career. He chose science, working on an influenza vaccine in the laboratory of Dr. Thomas Francis at the University of Michigan. Fifteen years later, Francis would supervise the critical test of Salk’s vaccine.
In 1943, while Salk was working on the influenza vaccine, 10,000 people, mostly children, contracted polio in the United States; in 1948, when Salk was first studying polioviruses at the University of Pittsburgh, 27,000 more people were affected; and in 1952, when Salk was first testing his polio vaccine in and around Pittsburgh, 59,000 more cases occurred. A national poll found that polio was second only to the atomic bomb as the thing Americans feared most. There was a desperate, growing desire to prevent polio.
Viruses, unlike bacteria, grow inside cells. To grow polioviruses in the 1930s, scientists John Kolmer and Maurice Brodie had used cells from monkey brains and monkey spinal cords. Salk, on the other hand, used cells from monkey testicles. Later, concerned that people would never accept a vaccine grown in monkey testicles, Salk switched to monkey kidney cells, which are still used to make polio vaccines today.
Because three different types of poliovirus cause disease, Salk knew that he would need to include representatives of all three types in his vaccine. For type 1, Salk chose the Mahoney strain—a decision that would haunt him for the rest of his life. The Mahoney strain was first recovered from a child in Akron, Ohio, whose last name was Mahoney. But the Mahoney strain wasn’t limited to the Mahoneys. The Klines, living next door, were also infected. Three of five Kline children were paralyzed and later died from the disease—an early clue to the unique horror of this particular strain. The other two strains of virus contained in Salk’s vaccine, representing types 2 and 3, weren’t controversial.