Medical Examiner

The Unsung Vaccinologist

Maurice Hilleman deserves the praise being lavished on Jonas Salk.

Maurice Hilleman, 1919-2005
Maurice Hilleman, 1919-2005

By dying Monday, on the eve of the 50th anniversary of the licensing of Jonas Salk’s famous polio vaccine, the great Maurice Hilleman has offered himself up as a vehicle for thinking about the nature of scientific celebrity. Salk’s major contribution to science pretty much ended with his delivery of the polio vaccine. Hilleman, on the other hand, either invented or helped develop vaccines for almost all of the other childhood illnesses—from measles, mumps, and rubella to hepatitis B and meningitis. His work protected hundreds of millions of children and in the process reshaped the world.

Not to knock Salk—plenty of others have taken their shots—but he had a knack for being photographed in his lab coat, peering meaningfully at a rack of test tubes. He spoke soothingly about the absolute safety of his product, though it wasn’t totally safe; vaccines never are. Postwar America loved Salk because it feared polio more than any other illness, though even at its peak the virus killed only a fraction of the number of people who die every year, even now, of the flu. Polio was scarier. It appeared insidiously in the homes of lowlife slobs and respectable middle-class people alike. And while other epidemics, however horrible, took their victims away in pine boxes, polio cripples usually survived, “limping through life as a constant reminder to their fellows of the terrible visitation which occurred,” as the writer John Rowan Wilson put it, depriving us “of one of our main protections against the horrors which afflict mankind—the capacity to forget.” When Salk killed polio, his reward was to be worshiped as a saint.

Yet while polio has never been forgotten, the diseases Hilleman stopped no longer seem threatening. Hilleman won the National Medal of Science in 1988. But he was never famous in the way Salk was famous. The simple explanation is that only fear creates heroes, and Americans no longer have to fear measles, thanks in part to Hilleman.

Also in contrast to Salk, Hilleman broadcast no saintly air. He was a towering, raccoon-eyed gentleman who had emerged improbably, by way of a Ph.D. from the University of Chicago, from a career as a J.C. Penney salesman on the blasted plains of Montana. His mother and twin sister died in childbirth, he believed as a result of the flu pandemic of 1918 and 1919. He was a gifted bullshit artist who enjoyed a good laugh at the expense of a rival who, say, had produced a vaccine that was making people sick. The jokes gave you the impression that Hilleman was crude and uncaring, and a little reckless. But his work was anything but. Once, at a meeting with researchers of a vaccine that protected against rotavirus, which causes diarrhea and dehydration, Hilleman said, “Here’s what you do. You get some of that stuff you made, go down to the poorest section of the city and give it to about 25 kids and see what happens.” The comment shocked everyone who was there to hear it. But it was merely bluster. In fact, Hilleman had gone out of his way to test his most famous vaccines, including those against the measles, mumps, and rubella trinity, in the well-to-do Philadelphia suburb of Havertown, Pa.

Two months after Salk’s vaccine came on the market in 1955, more than 200 people who’d been injected or exposed to it fell ill with crippling polio. Manufacturers hadn’t followed Salk’s recipe to the letter, and they’d allowed live virus to slip into the vaccine. Salk was no dummy, but he’d missed a few icebergs. Hilleman knew better. Despite his rough-and-ready manner, he was a nail-biter who through hard work (and occasionally luck) avoided such blunders—one reason that his career was long and profitable and in the end had a great deal more impact than Salk’s. Joining Merck in 1957, he mobilized the production of 20 million doses of flu vaccine, protecting the country from one of the last great flu pandemics. Later he revolutionized the poultry industry by creating a vaccine that prevented cancer in chickens. In all, he had a hand in developing three dozen vaccines, several of which are offered today to every American child.

Under Hilleman’s guidance, Merck avoided the polio and pertussis vaccines, which had the biggest safety problems. Yet he pushed the company to keep making other vaccines even during periods of low profitability, saying Merck had a moral responsibility to do so when it was reaping large profits from its drugs. Hilleman was willing to wield whatever instruments were at hand to get his way. One former Merck employee testified to Congress in 1972 that he had attended meetings where Hilleman roared, “Getting vaccine products licensed has nothing to do with science; it’s politics, not science that gets products licensed!”

Last November, the Los Angeles Times produced a 1991 memo from Hilleman in which he expressed concern about the amount of a mercury-containing preservative called thimerosal included in two new Merck vaccines against meningitis and hepatitis B. The memo has been seized upon by lawyers representing the parents of more than 8,000 children who are suing the government or the vaccine companies over thimerosal, which they claim made their children autistic. The lawsuits, which have already cost the pharmaceutical industry $200 million, could blow the vaccine enterprise out of the water if they succeed.

In a way, the thimerosal controversy is reminiscent of a flap in 1960 in which Hilleman was more deeply involved—his discovery, along with other scientists, that the tumorigenic virus SV40 was lurking in the polio vaccine. The virus may have caused human cancers decades later, though how many is a riddle. It’s also not clear whether thimerosal did any harm, and it may never be. The most damning claims by the plaintiffs suing over the preservative are that the FDA never tested it properly and that the CDC failed to notice, as it added new vaccines to the list it requires, that children might be getting doses of the stuff that could be cumulatively dangerous. But Hilleman, it turned out, did notice. “When viewed in this way, the mercury load appears rather large,” he wrote in the 1991 memo to Merck officials. “The key issue is whether thimerosal, in the amount given with the vaccine, does or does not constitute a safety hazard.”

Merck apparently bounced that observation off FDA officials, who apparently sat on it. How badly did they screw up? We don’t know yet. But we can still thank Hilleman for choosing a profession that protects children rather than the reputations of those who work in it.