A couple of weeks ago, I was researching the history of polio vaccination, and I stumbled across a photo that stopped me cold. There was Jonas Salk, the researcher who developed the polio vaccine we use in the US today, giving his son a shot. The caption reads: “Peter Salk receiving the inactivated poliovirus vaccine from his father, Jonas Salk. Salk also injected himself, his wife, and his two other sons. The vaccine was still experimental at this point.” And it wasn’t just Salk. Julius Youngner, who worked in the lab with Salk, told the Daily News in 1980, that he had given it to his children as well, and that all the lab members had been vaccinated. “You can’t ask other people to take it if you don’t give it to your own children,” he told the reporter. “People offered their children as volunteers.”
There are countless examples of scientists acting as their own guinea pigs. But testing an experimental vaccine on the fruit of your own loins? That seems like an entirely different level of lunacy. Salk’s youngest son Jonathan, who received the vaccine, later recalled, “He knew it worked. There was no risk in his eyes . . . He wanted his children to be protected.”
Jonathan has a point. Why should Salk’s actions strike me as reckless? At the time, polio posed a real and deadly threat. What’s more, Salk had plans to test his vaccine in hundreds of thousands of children. If Salk had said, “Yes, let’s test this vaccine in kids . . . other people’s kids,” wouldn’t that have been a kind of medical NIMBYism? And there’s no doubt that his actions sent a powerful message: If it’s safe enough for MY children, surely it’s safe enough for yours. News articles about Salk and his brilliant new vaccine rarely failed to mention the fact that Salk’s family had been immunized.
There’s no question Salk believed his vaccine was safe. In 1954, Life magazine ran a long article on the development of the polio vaccine. At that time, Salk had tested the vaccine in hundreds of children. “The advisory committee of the National Foundation, including men who are seasoned leaders in the field of virology, guarantees its safety,” Life reporter Robert Coughlan wrote. “So does Dr. Salk, a responsible scientist who, of course, would be ruined by any mistake in his work. ‘There is no question of ‘how safe is it?’’ he says. ‘It is safe, and it can’t be safer than safe.’”
Salk’s version of the vaccine did seem safe. The largest clinical trial in history, which enrolled 1.8 million children in the US, Canada and Finland, found the vaccine to be both safe and effective. “No medical study, before or since, approaches the 1954 Salk vaccine field trial in size, complexity, or the extent of public involvement,” wrote one historian. In 1955, the government approved the vaccine and drug makers began churning out product. Between April 15 and May 7, five companies distributed nearly 5 million doses of the vaccine.
“The Salk inactivated poliovirus vaccine is one of the most rapid examples of bench-to-bedside translation in medicine,” writes a group of researchers from Mayo Clinic. The vaccine made it from bench to bedside in just six short years. But this seeming successful story of rapid translation soon took a dark turn.
After the vaccine was licensed, reports began to surface of children who had received the vaccine and then become paralyzed. At first, experts were quick to defend the vaccine. They argued that these children had most likely contracted polio before they were vaccinated. Seven-year-old Pamela Erlichman took ill soon after receiving the vaccine. The paralysis began in her left arm, but it soon spread. Days later she was dead. Her father, a physician, told The Pittsburgh Press that he didn’t believe that the vaccine had caused her death and that he would let his six-year-old son James get his second polio shot.
But as the caseload mounted, the connection became hard to ignore. Tellingly, most of the children who developed polio had received vaccine produced by one particular drug company — Cutter Laboratories. There was one more clue: Paralysis due to polio typically begins in the legs. But many of these children developed paralysis in the arm where the shot had been administered. Officials eventually figured out that the problem was poor quality control. Salk’s vaccine relies on polio virus that has been inactivated to prompt an immune response. Salk killed the virus by bathing it in a formaldehyde solution. But that process takes some time, and a handful of the drug companies had been having trouble ensuring that their virus was actually dead. Consequently, some children received vaccine that contained live virus, perfectly capable of replicating and causing paralysis. [These manufacturing problems have long since been rectified, and the inactivated polio vaccine used today does not cause polio. The oral vaccine, which contains live poliovirus, can cause paralysis in rare instances.]
This public health disaster wasn’t Salk’s fault. But it makes me wonder whether Salk’s unshakable confidence was misguided. He had to know that safe doesn’t mean risk free. Every vaccine, every medicine, every therapy can have unintended consequences. If one of Salk’s sons had died of polio after being vaccinated, would we still be using his vaccine? If Salk had refused to vaccinate his sons, would other parents have been so willing to vaccinate theirs?
Image credit: Wikimedia Commons