Pioneers of protection we take for granted
Susan Okie applauds a detailed study of how vaccines were developed and the good they do
The Vaccine Race: Science, Politics, and the Human Costs of Defeating Disease by Meredith Wadman Viking, 436pp
Growing up in the 1950s and 60s, I suffered through chicken pox and measles, like millions of other American kids, and belonged to the first generation to receive the new polio vaccines in national campaigns. My parents had friends permanently paralysed by polio; the mother of a schoolmate gave birth to a baby who was deaf, nearly blind and suffering a severe intellectual disability from rubella (German measles) contracted during pregnancy.
Within a half-century, vaccines have made these and other once-common viral diseases so rare in the US that doctors being trained today may never see cases of them, and some parents worry more about the small or hypothetical risks of vaccinating children than about the risks of leaving them unprotected. It takes events such as the 2015 measles outbreak among visitors to Disneyland in California or the emergence of the Zika virus to remind us not to take our freedom from infectious diseases for granted.
In this meticulously researched history of the race to develop vaccines against polio, rubella, rabies and other viruses, science writer and doctor Meredith Wadman tells the story of these nearmiraculous medical achievements of the post-second world war era. The Vaccine Race also details the risks posed by some of the early products – risks that arose, in part, because to make the vaccines, researchers first had to invent techniques for growing viruses in living cells, without knowing what other viruses those host cells might harbour. Even when a government scientist, Bernice Eddy, and colleagues showed that monkey cells used to produce the Salk polio vaccine and other vaccines contained a virus, SV40, that could cause malignant changes in human cells, officials at first discounted the evidence and allowed such vaccines to remain on the market. By 1963, when the federal Division of Biologics Standards in the US began to require that polio vaccines be free of SV40, 98 million Americans had received the Salk vaccine, indisputably preventing tens of thousands of cases of paralysis from polio. But between 10 million and 30 million of them may have received a dose contaminated by the SV40 virus. Whether such exposure increased their likelihood of developing cancer remains uncertain. The Institute of Medicine “concluded in 2002 that although studies that followed vaccine recipients over the decades provide no evidence of increased cancer risk, these studies were ‘sufficiently flawed’ that the question ... couldn’t be answered,” Wadman writes.
Early vaccines against viral diseases were designed to stimulate the immune system by giving the recipient either a dead or a weakened version of the virus they were intended to protect against. In live-virus vaccines, choosing the right strength and strain of the virus was a challenge. If it was too strong, the vaccine might cause full-blown cases of the illness; if too weak, it might not produce lasting immunity. Live-virus vaccines are used today to protect against certain infections, including measles, mumps, rubella and chicken pox. Newer vaccines against some other diseases are genetically engineered to contain only proteins from the coat of the virus. Thus, they cannot cause the infection.
In the postwar decades, researchers and drug companies competed intensely to be the first to license vaccines against certain diseases. The need was urgent. Polio paralysed an average of 15,000 Americans each year. Rubella epidemics occurred every few years and were devastating for women infected during pregnancy. The nationwide epidemic of 1964-65 caused about 6,250 miscarriages or stillbirths, 2,100 deaths among newborns, and 20,000 cases of congenital birth defects. An additional 5,000 pregnant women had abortions after contracting rubella. Rabies, considered the most deadly of all infections in humans, was on the rise in wild animals in the early 1960s.
At the time, government standards on the ethics of human research were rudimentary to nonexistent. As Wadman describes, vaccines were tested in circumstances shocking to a reader today. Experimental vaccines were given to newborn or premature babies, to prisoners, and to mentally or physically disabled residents of institutions, often without consent, and with minimal institutional oversight. The first humans to receive a live polio vaccine, in 1950, were 20 intellectually disabled children at Letchworth Village, an institution in rural New York. Babies born to women imprisoned at Clinton State Farms in New Jersey were given an experimental polio vaccine over a five-year period in the late 1950s. The prison’s popular female warden and medical director “were extremely helpful in obtaining permission” from the mothers, the researchers later noted.
Wadman relates this fascinating history as lived by a handful of scientists at the centre of it all, especially Leonard Hayflick, an indefatigable cell biologist who refined techniques for growing, maintaining and infecting human cells with viruses to make safer, better vaccines, and Stanley Plotkin, a paediatrician and vaccinologist who studied the rubella virus and developed a safe vaccine against it.
Hayflick reasoned that cells taken from human foetuses, which are protected from most infections (though not rubella) in the womb, would probably be free of viruses and thus far less risky than animal cells for vaccine production. Through connections in Sweden, he obtained tissue from aborted foetuses, including, in 1963, lung tissue from the foetus of a Swedish woman referred to as Mrs X. The cultured lung cells gave rise to a cell line called WI38 – vigorous, healthy and virus-free. It is still used today. Eventually, as biology became big business, the ampoules of frozen WI-38 founder cells proved a valuable commodity, sparking an ugly tug-of-war over their ownership among Hayflick; his longtime boss, Hilary Koprowski of Philadelphia’s Wistar Institute; and officials at the National Institutes of Health. Wadman traces the twists in this colourful dispute with admirable balance.
Plotkin used Hayflick’s WI-38 cells to grow a weakened strain of rubella virus that he needed to make his vaccine. The strain he chose came from the infected kidney cells of another foetus, one whose mother had undergone an abortion after contracting rubella during pregnancy. Thus, the protection from disease conferred by Plotkin’s rubella vaccine, and by other vaccines made using WI38 cells, is directly linked to the use of these cells from aborted foetuses. “I am moved by the intimate interaction between the WI-38 cells and the hundreds of millions of people who have benefited from ... vaccines made using them,” Wadman writes. “When they are vaccinated, they are literally, physically connected to Mrs X’s foetus.” Although debate continues over the use of foetal tissue in research, it is legal in the United States and is contributing to scientists’ understanding of numerous diseases, as well as development of new treatments.
At almost 400 pages of text plus abundant endnotes, this book is so rich in scientific anecdotes, historical detail and quirky characters that I can’t
do it justice in a short review. Wadman conjures the wizardry of Hayflick’s cell laboratory; the brick vastness of long-gone Philadelphia General Hospital, which cared for the city’s workers and poor; the medical acumen of Australian eye surgeon Norman McAlister Gregg, who made the connection between pregnant women with rubella and babies born blind. She conveys the era’s no-holdsbarred approach to science, as well as the altruism of individual scientists and doctors at a time when no one had yet thought of patenting a gene or a living cell. Her dissection of the role played by abortion in vaccine development provides valuable context for today’s abortion politics, and her chapter on the stirrings of entrepreneurship among biologists and universities is an enlightening primer on the birth of the biotech industry. Washington Post