Deadly Choices: How the Anti-Vaccine Movement Threatens Us All - Paul A. Offit (2010)

Chapter 8. Tragedy of the Commons

Freedom is the recognition of necessity.

—GEORG WILHELM FRIEDRICH HEGEL

Parents in nineteenth-century England argued that vaccines were impure or unsafe or an act against nature or God. But their anger wasn’t directed at doctors so much as at government officials who had no right to tell them what to do—no right to tell them what should be injected into their children. To protesters, compulsory vaccination was an intolerable violation of their civil liberties.

In America, the response to state-mandated vaccines was no different. Indeed, one citizen’s fight went all the way to the Supreme Court. The ruling in that case—called “the most important Supreme Court case in the history of American public health”—has been cited in seventy Supreme Court verdicts and, for more than a century, has determined whether states can force parents to vaccinate their children.

It started with a Lutheran minister in Massachusetts.

In May 1899, a case of smallpox occurred in the city of Swamp-scott, twelve miles outside Boston. By summer, several more cases appeared in Everett and Charlestown, just across the Charles River. By 1901, more than two hundred Bostonians had fallen victim to the disease. In response, the Cambridge Board of Health proclaimed: “Whereas, smallpox has been prevalent in this city of Cambridge and has continued to increase; and whereas it is necessary for the speedy extermination of the disease; be it ordered that all inhabitants of the city be vaccinated.” Citizens who refused were fined $5.00. By early 1902, more than 485,000 had been vaccinated. The Boston Daily Globe declared, “There is a greater demand for vaccination in Boston than there is for salvation, even though both are free.” In 1903, when the epidemic ended, smallpox had infected sixteen hundred people and killed almost three hundred. If city health officials hadn’t acted, the toll would have been much greater.

Not everyone embraced the city’s mandate. On March 15, 1902, Dr. Edwin Spencer visited the home of Henning Jacobson and offered to vaccinate him. Jacobson refused—then he refused to pay the fine.

Henning Jacobson was born in Sweden in 1856, coming to the United States when he was thirteen years old. In 1882, while a student at a Lutheran college in Minnesota, Jacobson married Hattie Alexander and together they had five children. In 1893, the Church of Sweden Mission Board asked him to found a Lutheran church in Cambridge, Massachusetts. A pious man, charismatic orator, and community organizer, Jacobson was devoted to his congregants; his fundamental belief that God would protect him was at the heart of his refusal to vaccinate.

In July 1902, Jacobson was tried before a Middlesex county district court. After a jury found him guilty, Jacobson appealed to the county’s superior court, which, in February 1903, upheld the conviction. Undeterred, Jacobson appealed to the state supreme court. This time, two well-known lawyers represented him: Henry Ballard of Vermont and James Pickering, a Harvard-trained lawyer who would later win fame as the oldest U.S. soldier in World War I. Given their fees and his meager pastor’s salary, Jacobson’s choice of Ballard and Pickering was surprising. But Pickering lived only a few blocks from Immanuel Pfeiffer, a leader of Boston’s Anti-Vaccination League. It was Pfeiffer who had convinced Pickering to take the case.

Pickering and Ballard argued that the state had violated Jacobson’s civil rights: “Can the free citizen of Massachusetts, who is not yet a pagan, not an idolator, be compelled to undergo this rite and to participate in this new—no, revised—form of worship of the Sacred Cow?” 

Again, Jacobson lost. So he took his case to the highest court in the land. On June 29, 1903, the United States Supreme Court added Jacobson v. Massachusetts to its docket. This time Jacobson chose George Williams, a former congressman from Massachusetts, to represent him. Williams argued that Massachusetts, by requiring vaccination, had violated the Fourteenth Amendment—specifically, that no state could deprive any person of life, liberty, or property without due process of law. Williams’s legal brief stated, “A compulsory vaccination law is unreasonable, arbitrary, and oppressive, and, therefore, hostile to the inherent right of every freeman to care for his own body and health in such a way as to him seems best.” Williams also argued that vaccines were unconscionably dangerous: “We have on our statute book a law that compels ... a man to offer up his body to pollution and filth and disease; that compels him to submit to a barbarous ceremonial of blood-poisoning, and virtually to say to a sick calf, ‘Thou art my savior; in thee I do trust.’”

Henning Jacobson was at the center of a landmark U.S. Supreme Court ruling on the right of citizens to resist vaccination. (Courtesy of the Evangelical Lutheran Church in America Archives.)

On February 20, 1905, the Supreme Court—by a vote of 7 to 2—ruled that the right to refuse vaccination wasn’t guaranteed by the U.S. Constitution. Writing for the majority, Justice John Marshall Harlan argued that, in the arena of public health, societal good trumped individual freedom: “The liberty secured by the Constitution of the United States to every person within its jurisdiction does not import an absolute right to each person to be, at all times and in all circumstances, wholly freed from restraint. There are manifold restraints to which every person is necessarily subject for the common good. Society based on the rule that each one is a law unto himself would soon be confronted with disorder and anarchy.” Harlan described the Cambridge Board of Health law compelling vaccination as a “fundamental principle of the social compact that the whole people covenants with each citizen, and each citizen with the whole people.”

Jacobson v. Massachusetts wasn’t the only time the Supreme Court considered a state’s right to mandate vaccines. Seventeen years later, in 1922, officials from Brackenridge High School in San Antonio, Texas, expelled fifteen-year-old Rosalyn Zucht because her parents refused to vaccinate her. Unlike Boston in the early 1900s, San Antonio wasn’t in the midst of a smallpox epidemic. But that didn’t matter. In a unanimous decision the court ruled that Rosalyn’s expulsion didn’t violate her constitutional rights.

The rulings in Jacobson and Zucht gave states the right to enforce vaccination. But they didn’t set limits on how far public health officials could go. In some states, for example, parents could be criminally prosecuted. But the event that probably worried antivaccine activists more than any other occurred in New York City in 1909. One health officer involved in the case later said, “There is very little that a Board of Health cannot do in the way of interfering with personal and property rights for the protection of public health.” The officer was referring to the strange case of Mary Mallon.

Mary Mallon was born in Ireland on September 23, 1869, immigrating as a teenager to the United States, where she became a cook for wealthy New Yorkers. In 1906, Mallon was working on Oyster Point, Long Island, for a New York City banker named Charles Warren. Warren had rented the house on Oyster Point from George Thompson. That summer, six people in Warren’s family were struck down by typhoid fever.

At the turn of the twentieth century, typhoid fever was a well-recognized problem, infecting as many as thirty-five thousand Americans every year. The disease is caused by the bacterium Salmonella typhi, which at that time regularly contaminated food and water. Typically, victims had fever, headache, and malaise followed by chills, loss of appetite, and a rash on the chest and abdomen. After the rash disappeared, people often got sicker, with severe cramping and weight loss and, in some cases, decreased blood pressure and shock. One in ten died from the disease.

When Thompson found that half of Warren’s family had contracted typhoid fever, he hired George Soper, a sanitary engineer, to find the source. Soper did his homework, uncovering a series of outbreaks similar to the one on Oyster Point. He found one case in 1900 on Long Island; another in 1901 in New York City; seven in 1902 in Dark Harbor, Maine; four in 1904 among servants in Sands Point, New York; and three in 1906: one in Tuxedo Park, New York, and two on Park Avenue in New York City. All these outbreaks had one thing in common: Mary Mallon was the cook. Twenty-two people had been infected; two had died. When Soper was investigating the outbreaks, Salmonella typhi was known to contaminate food. But when cooks spread the disease, they were always sick as well. Mallon, on the other hand, had no symptoms of the illness. Indeed, Mary Mallon was the first person in North America found to be a healthy carrier of Salmonella typhi.

After Soper identified Mallon as the likely source of the Warren family outbreak, he wanted to prove it. “I had my first talk with Mary in the kitchen,” he recalled. “I was as diplomatic as possible, but I had to say I suspected her of making people sick and that I wanted specimens of her urine, feces, and blood. It did not take Mary long to react to this suggestion. She seized a carving fork and advanced in my direction.” Eventually, Soper gave up, leaving the task of collecting specimens to Josephine Baker, a New York City public health official. On March 19, 1907, Baker, accompanied by a police officer, visited Mary Mallon. “She came out fighting and swearing,” recalled Baker, “both of which she could do with appalling efficiency and vigor.

There was nothing I could do but take her with us. The policeman lifted her into the ambulance and I literally sat on her all the way to the hospital; it was like being in a cage with an angry lion.” Baker took Mallon to the Willard Parker Hospital, then to New York’s receiving unit for contagious diseases. There, microbiologists found that her feces were teeming with typhoid bacilli. Immediately, Baker sent Mallon to North Brother Island in the East River, where she lived in a small bungalow, alone, cooking for herself. Mallon didn’t understand her incarceration. “I never had typhoid in my life,” she said, “and have always been healthy. Why should I be banished like a leper and compelled to live in solitary confinement with only a dog for a companion?” Three years later, health authorities released Mallon after she promised she would no longer work as a cook. The press dubbed her “Typhoid Mary.”

Mary Mallon (left), “Typhoid Mary,” the first person in the United States identified as a carrier of typhoid bacilli, was confined on North Brother Island from 1907 to 1910 and then from 1915 until her death in 1938. (Courtesy of Bettmann/Corbis.)

In 1915, an outbreak of typhoid fever occurred at Sloane Maternity Hospital in New York City. Twenty-five doctors, nurses, and hospital staff were infected and two died. Investigators traced the source of the epidemic to Mrs. Brown, a cook who had been employed three months earlier. It didn’t take long for health officials to realize that Mrs. Brown was Mary Mallon. “Whatever rights she once possessed as the innocent victim of an infected condition were now lost,” said George Soper. “She was now a woman who could not claim innocence. She was known willfully and deliberately to have taken desperate chances with human life. She had abused her privilege; she had broken her parole. She was a dangerous character and must be treated accordingly.” On March 26, 1915, state health officials again sent Mary Mallon to North Brother Island, where she remained for the rest of her life, dying of a stroke on November 11, 1938. Mallon had spent twenty-six of her sixty-nine years quarantined as a carrier of Salmonella typhi, never having exhibited a single symptom of the disease.

American anti-vaccine activists watched what had happened to Mary Mallon—and it scared them. They wondered just how far public health officials would go in their quest to vaccinate children.

Following the Supreme Court’s decision in Jacobson v. Massachusetts, an editorial appeared in the New York Times: “The contention that compulsory vaccination is an infraction of personal liberty and an unconstitutional interference with the right of the individual to have the smallpox if he wants it, and to communicate it to others, has been ended. [This] should end the useful life of the societies of cranks formed to resist the operation of laws relative to vaccination. Their occupation is gone.” The prediction couldn’t have been more wrong. Anti-vaccine activism in the United States was just getting started.

In 1894, in response to a smallpox outbreak in Brooklyn, the Board of Health ordered Charles McCauley, his wife, and son to be vaccinated. They refused, the elder McCauley threatening the visiting doctor with a rifle. In response, the McCauleys were quarantined; two policemen stood at their door. The New York Times reported the incident: “They were forbidden to leave the apartment, and the other tenants were warned, under penalty of arrest, not to deliver any messages to them. The grocers, butchers, and bakers in the vicinity were also forbidden to deliver provisions.” The next day, police found a two-foot hole in a closet through which the family had escaped, eventually making it to Hoboken, New Jersey. Three days later, after public health officers convinced the McCauleys they had nothing to fear from the procedure, they surrendered to the Brooklyn police and were vaccinated.

In the late 1890s, incidents similar to that of the McCauleys spawned anti-vaccine groups like the Brooklyn Compulsory Anti-Vaccination League and the Massachusetts Compulsory Anti-Vaccination Association. Local leagues became national organizations. In 1908, two wealthy businessmen, John Pitcairn and Charles Higgins, founded the Anti-Vaccination League of America, a coalition of many smaller groups. Pitcairn declared, “We have repudiated religious tyranny; we have rejected political tyranny; shall we now submit to medical tyranny?” Pitcairn was the orator; Higgins the pamphleteer, producing Open Your Eyes Wide! (1912), The Crime Against the School Child (1915), Vaccinations and Lockjaw: The Assassins of the Blood (1916), and Horrors of Vaccination Exposed and Illustrated (1920). One of the most active anti-vaccine groups was the Citizens’ Medical Reference Bureau. Founded in New York City in 1919, the group produced the popular pamphlet The Facts Against Compulsory Vaccination: It’s the School and Not the Child That Is Public.

But of all the anti-vaccine activists at the turn of the century, the most vocal, most passionate, and most irascible was Lora Little, founder of the American Medical Liberty League. Little was moved to action by the death of her son, Kenneth, following a smallpox vaccine. Although the child had actually died from measles and diphtheria, Little was convinced that vaccination was the cause. Like Barbara Loe Fisher, Lora Little believed that doctors and health officials were all part of a conspiracy to sell vaccines. In her pamphlet, Crimes of the Cowpox Ring, Little sounded themes of antivaccine activists past and future: “The salaries of the public health officials in this country reach the sum of $14,000,000 annually. One important function of the health boards is vaccination. Without smallpox scares their trade would languish. Thousands of doctors in private practice are also beneficiaries in ‘scare’ times. And lastly, the vaccine ‘farmers’ represent a capital of $20,000,000 invested in their foul business.”

The Raggedy Ann doll was created in part to represent children permanently harmed by vaccines. (Courtesy of Lambert/Getty Images.)

Anti-vaccine activity in America also produced a popular icon. In 1915, Johnny Gruelle, a cartoonist and illustrator in New York City, watched his daughter, Marcella, die following a smallpox vaccine. Even though the medical report stated that the child had died from a heart defect, Gruelle blamed the vaccine. In his daughter’s memory, he created a doll with red yarn for hair and floppy arms and legs—a symbol of children harmed by vaccines. He called it Raggedy Ann.

By the 1930s, as the need for smallpox vaccine declined, so did the passion of anti-vaccine groups. The Anti-Vaccination League of America lost its voice when Charles Higgins died in 1929, as did the American Medical Liberty League when Lora Little died two years later. Massive programs promoting diphtheria vaccine in the 1930s and polio vaccine in the 1950s failed to incite anti-vaccine activity. It would be another fifty years, until the airing of DPT: Vaccine Roulette, before the nationwide anger spurred by state-enforced vaccination reemerged. But the fight against compulsory vaccination in court was far from over.

In the late 1960s and early 1970s, public health officials at the CDC decided to eliminate measles from the United States. Their method sparked a series of lawsuits.

In the first half of the twentieth century, measles caused thousands of hospitalizations and hundreds of deaths every year. With the invention of a vaccine in 1963—and buoyed by the virtual elimination of smallpox and polio—the CDC saw an opportunity. Because measles occurred primarily in school-aged children, health officials reasoned that the best way to eliminate it would be to mandate vaccine for school entry. A famous photograph at the time—and one shown on Vaccine Roulette—was that of the CDC’s Alan Hinman holding up a sign that read “No Shots, No School.”

The CDC picked an opportune moment to launch its attack. Although measles vaccine had caused a dramatic decline in the disease, immunization rates had become stagnant. And measles cases increased. In 1970, forty-seven thousand cases were reported. By 1971, the number had risen to seventy-five thousand.

In addition to state health officials, CDC efforts drew on two powerful political groups. The first was the Joseph P. Kennedy Foundation, the second was that of Betty Bumpers. Kennedy was the father of President John F. Kennedy and senators Robert and Edward Kennedy. He was also the father of Rosemary Kennedy. Severely retarded from birth, Rosemary was lobotomized in 1941 and institutionalized from 1949 until her death in 2005. Moved by her struggle, the Kennedy Foundation provided services for the mentally disabled. The foundation was interested in measles because the virus caused encephalitis in four thousand Americans a year, often resulting in permanent brain damage. At the time of the CDC initiative, Edward Kennedy was a senator from Massachusetts and his sister, Eunice Kennedy Shriver, was head of the U.S. Office of Economic Opportunity, created as part of Lyndon Johnson’s Great Society. Writing to governors and congressmen, the Kennedys used their considerable influence to promote the enactment and enforcement of local school-entry mandates.

Bumper sticker displayed by South Carolina public health officials in 1980. (Courtesy of Dr. Alan Hinman.)

Whereas the Kennedys provided an emotional impetus for school requirements, Betty Bumpers, wife of Arkansas senator Dale Bumpers, provided a financial one. Recruiting First Lady Rosalynn Carter to her cause, in the early 1970s Bumpers helped create a federally funded program called the Childhood Immunization Initiative that bought vaccines for children whose parents couldn’t afford them. Through her efforts, federal funding for vaccines increased from $5 million in 1975 to $17 million in 1976 to $23 million in 1977. In addition, in response to a deadly measles epidemic in the early 1990s, Betty Bumpers and Rosalynn Carter founded Every Child by Two (ECBT), a nonprofit organization. ECBT organizes educational programs in cities with low immunization rates and supports efforts to vaccinate children in Africa.

One result of these efforts was that the number of states requiring vaccines for school entry increased from twenty-five in 1968 to forty in 1974—a situation that provided a natural experiment to see whether school mandates worked. At first, they didn’t seem to: outbreaks of measles continued. The problem, it turned out, wasn’t that health officials didn’t have school-entry requirements; it was that they didn’t enforce them. But the tide was about to turn.

In 1976, during a massive measles outbreak in Alaska, state health officials informed parents that their children couldn’t come to school until they were immunized. Fifty days later, after more than seventy-four hundred students hadn’t complied, health officials excluded them from school. Within a month, fewer than fifty children remained unvaccinated and the epidemic ended.

In 1977, a measles epidemic occurred in Los Angeles County; thousands of children were infected, many suffered measles pneumonia, three had measles encephalitis, and two died. On March 31, the county health director declared that any child who had not had a measles vaccine by May 2 would not be allowed in school. When the deadline arrived, tens of thousands of students still hadn’t been vaccinated. As in Alaska, Los Angeles County parents soon realized that health officials weren’t kidding—fifty thousand children were barred from school. Within days, most were back with proof of immunity, again ending the epidemic.

Although events in Alaska and Los Angeles County were compelling, the most dramatic example of the power of school mandates occurred in Texarkana, a city that straddles the border between Texas and Arkansas. Between June 1970 and January 1971 Texarkana suffered 633 cases of measles. At the time of the outbreak, Arkansas required vaccines for school entry and Texas didn’t. Of the 633 cases, 608 (96 percent) occurred in Bowie County (the Texas side) and 25 (4 percent) occurred in Miller County (the Arkansas side).

By 1981, all fifty states had school immunization requirements. During the next two decades, with greater enforcement, the number of measles cases declined dramatically. In 1998, only eighty-nine cases of measles occurred in the United States, most imported from other countries.

Walter Orenstein was a young epidemiologist at the CDC during the 1977 measles outbreak in Los Angeles: “The school mandate [in Los Angeles] really changed everything,” he recalled. “That set the precedent for no shots, no school. The beauty of the school laws is that we didn’t have policemen forcing people against their will to be vaccinated. We just said if you are unwilling to be vaccinated, you can’t go to school.” Orenstein was drawing a legal distinction between compulsory vaccination, in which people who refuse are forcibly vaccinated, and mandatory vaccination, in which people who refuse are denied social privileges, like attending public school.

Despite the remarkable success of school mandates, the heavy hand of health officials provoked a backlash. Some parents couldn’t accept that their unvaccinated children could be denied an education. So they sued the states, claiming protection under the First Amendment, which requires that “Congress shall make no law respecting an establishment of religion or prohibiting the free exercise thereof....” The ruling that tipped the balance in these First Amendment cases wasn’t the Supreme Court ruling in Jacobson or Zucht. It was one that on its surface had nothing to do with vaccines.

On December 18, 1941, Sarah Prince, a Jehovah’s Witness, took her two sons and nine-year-old niece, Betty Simmons, “to engage in the preaching work with her upon the sidewalks.” Prince had been warned by a school-attendance officer that bringing children with her at night violated state labor laws, but she ignored the warning. At 8:45 p.m., “Betty held up in her hand, for passers-by to see, copies of ‘Watchtower’ and ‘Consolation.’ From her shoulder hung the usual canvas magazine bag.” The truant officer again warned Prince to get the children off the street. “Neither you nor anyone else can stop me,” threatened Prince. “The child is exercising her God-given right and her constitutional right to preach the gospel, and no creature has a right to interfere with God’s commands.” The case, known as Prince v. Massachusetts, reached the U.S. Supreme Court in 1943, and in January 1944 the court ruled against Prince, arguing that religious freedom didn’t trump child-labor laws. Justice Wiley B. Rutledge, who wrote the majority opinion for the court, then went beyond the case in front of him: “The right to practice religion freely does not include liberty to expose the community or the child to communicable disease or the latter to ill health or death. Parents may be free to become martyrs themselves, but it does not follow that they are free, in identical circumstances, to make martyrs of their children.”

The ruling had a major impact on vaccine lawsuits. In 1965, the Wrights, members of the General Assembly and Church of the First Born, argued unsuccessfully that DeWitt High School in Arkansas County, Arkansas, had violated their right to exercise their religion by requiring a smallpox vaccine for their children. In 1968, Thomas McCartney, a chiropractor and Roman Catholic, argued unsuccessfully that school officials in Broome County, New York, had violated his religious freedom by requiring a polio vaccine for his ten-year-old son. In 1974, Ronald Avard argued unsuccessfully that the public school system in Manchester, New Hampshire, had violated his religious freedom by dismissing his unvaccinated six-year-old son from kindergarten. In 1979, Charles Brown, a chiropractor and member of the Church of Christ, argued unsuccessfully that the school board in Houston, Mississippi, had violated his religious freedom by dismissing his unvaccinated six-year-old son from first grade. In 1982, Irving Davis, a member of the Church of Human Life Science, argued unsuccessfully that school officials in Cecil County, Maryland, had violated his religious freedom by not allowing his unvaccinated eight-year-old son to enter school.

The judges in each of these cases ruled that the right to practice religion freely hadn’t been violated because vaccination was required of all religions, without discrimination. However, a little-publicized bill in New York State had already opened a crack in the door—a crack that would have a major impact on the spread of contagious diseases in the United States. On June 20, 1966, New York State assemblymen voted on a bill requiring polio vaccine for school entry. There was one catch. The bill excluded children whose parents’ religion forbade vaccination, a direct result of lobbying by what was then one of the most powerful religious groups in the United States: Christian Scientists. The bill passed by a vote of 150 to 2. One of the dissenters, Joseph Margiotta, later explained his reasoning. “Suppose an exempted child was a polio carrier,” he said. Margiotta’s concern proved prescient.

Founded in 1879 by Mary Baker Eddy, Christian Scientists believed that illness was a mental, not physical, disorder. In her book Science and Health, Eddy wrote, “We have smallpox because others have it, but mental mind, not matter, contains and carries the infection.” Diseases like smallpox could be avoided by prayer, not by vaccines. Those who chose to follow Eddy’s teachings have paid the price.

In 1982, nine-year-old Debra Kupsh died of diphtheria at a Christian Scientist camp in Colorado. In 1985, three students died of measles at Principia College, a Christian Scientist school in Elsah, Missouri. At the time, the CDC’s Walter Orenstein noted that the high rate of measles deaths at Principia resembled “the kind of mortality statistics we see in the Third World.” The 1985 outbreak wasn’t the end of it; four more measles outbreaks occurred among Christian Scientist students in the St. Louis area between 1985 and 1994.

But the incident that attracted the most attention occurred in the fall of 1972, when a Christian Scientist high school in Greenwich, Connecticut, suffered a polio outbreak. Eleven children were paralyzed. At the time of the outbreak, not a single case of polio had occurred in Connecticut in more than three years. One health commissioner was so shaken that he wrote an editorial in the New England Journal of Medicine: “Although I am not arguing for absolute state control of the lives of private citizens, I am deeply bothered by the fact that disease prevention measures of documented benefit can be withheld from children by their parents in the name of religious freedom, jeopardizing not only the health and lives of the children so denied but those of the community as well. The courts of this land have long since set precedent in the protection of children from the irresponsible acts of their parents.”

The successful lobbying of Christian Scientists to include a religious exemption in New York State changed the strategy of those who wanted to avoid vaccines. Two seminal rulings opened the floodgates. The first involved William Maier and his three children—all of whom had been excluded from Fabius Central School in Onondaga County, New York. Maier argued that, although he wasn’t a Christian Scientist, he, like they, believed that “the sanctity of the human body cannot be violated by injection,” and that his beliefs were entitled to the same protection as a Christian Scientist’s. The judge agreed. The second ruling allowing religious exemptions involved Beulah Dalli, a mother in Lowell, Massachusetts. Dalli argued that her six-year-old daughter, Belinda, had been unfairly excluded from school because she wasn’t vaccinated. Although Dalli, like Maier, wasn’t a Christian Scientist, she believed that the use of vaccines was a violation of the Bible and its teachings, specifically the admonition to “keep the body clean and acceptable to God.” The court ruled in her favor, stating that it was unfair to allow vaccine exemptions for some religious groups but not others. By 2009, forty-eight states allowed religious exemptions to vaccination.

Religious exemptions opened the door to philosophical exemptions. A critical ruling in the late 1980s involved two Northport, New York, couples: the Sherrs and the Levys. Alan Sherr, a chiropractor, argued that his religion—a mail-order church in Sarasota, Florida, called the Missionary Temple at Large of the Universal Religious Brotherhood, Inc.—believed that vaccines represented an unwanted intrusion into the body. However, because Sherr had circumcised his son and allowed dentists to fill his son’s cavities, the intrusion argument didn’t hold. The Levys, on the other hand, were more compelling. Louis Levy argued that the state should not be allowed to force his daughter, Sandra, to be vaccinated because “We feel that any introduction into the process of a foreign element outside the normal processes of the body is going to affect the body adversely and, therefore, we feel it is a violation in a sense of our nature—physical, spiritual, religious nature.” The judge ruled in Levy’s favor, stating that vaccine exemptions could be granted if “beliefs [were] held with the strength of religious convictions,” even if parents weren’t members of a religious group. By 2010, twenty-one states allowed philosophical exemptions to vaccination.

By the late 1890s, the anti-vaccine movement in England had spawned the Anti-Compulsory Vaccination Act. If citizens didn’t want to be vaccinated, they could obtain a certificate of conscientious objection. As more and more citizens opted out, England became the United Kingdom’s epicenter of smallpox disease. By the early twenty-first century, American anti-vaccine activists—through passages of religious and philosophical exemptions—had also impacted the public’s health. Between 1999 and 2009, four studies examined whether the freedom to avoid vaccines also meant the freedom to catch and transmit infections.

In 1999, Daniel Salmon and co-workers from the Johns Hopkins School of Public Health found that the risk of contracting measles in five- to nine-year-olds whose parents had chosen not to vaccinate them was one hundred and seventy times greater than for vaccinated children.

In 2000, Daniel Feikin and his colleagues from the Respiratory Diseases Branch at the CDC found that three- to ten-year-olds in Colorado whose parents had chosen not to vaccinate them were sixty-two times more likely to catch measles and sixteen times more likely to catch whooping cough. They also found that measles outbreaks were more common in schools with greater numbers of unvaccinated children.

In 2006, Saad Omer and his colleagues, also from the Johns Hopkins School of Public Health, examined the impact of philosophical exemptions. Between 1991 and 2004, the number of unvaccinated children in states with philosophical exemptions more than doubled. Children in states with easy-to-obtain exemptions (granted by the simple signing of a form) were almost twice as likely to suffer outbreaks of whooping cough.

In 2009, Jason Glanz and his co-workers from the Institute for Health Research in Denver—confirming previous studies—found that unvaccinated children in Colorado were twenty-three times more likely to suffer whooping cough.

The impact of anti-vaccine activism hasn’t been limited to England and the United States. Studies have shown that the risk of whooping cough was ten to a hundred times greater in countries where immunization had been disrupted by anti-vaccine movements (such as Sweden, Japan, the Russian Federation, Ireland, Italy, and Australia) than in countries that had maintained high vaccination rates (such as Hungary and Poland).

The results were in. A choice not to get a vaccine was a choice to increase the risk of suffering and possibly dying from an infectious disease. Worse still, it was a choice to put one’s neighbor at greater risk. So why are more and more parents choosing not to vaccinate their children? The answer can be found in part in the writings of a professor of biology at the University of California at Santa Barbara who has explained why, under certain circumstances, a choice not to get a vaccine is far more rational than a choice to get one.

In 1968, Garrett Hardin published an essay in the journal Science called “The Tragedy of the Commons.” Hardin was interested in the problem of population control, but his observations can easily be applied to the problem of vaccine refusal. “Picture a pasture open to all,” he wrote. “It is to be expected that each herdsman will try to keep as many cattle as possible on the commons. As a rational being, each herdsman seeks to maximize his gain. He asks, ‘What is the utility to me of adding one more animal to my herd?’ The utility has one negative and one positive component.”

Hardin continued: “The positive component is a function of the increment of one animal. Since the herdsman receives all the proceeds from the sale of the additional animal, the positive utility is nearly +1. The negative component is a function of the additional overgrazing created by one more animal. Since, however, the effects of overgrazing are shared by all the herdsmen, the negative utility for any particular decision-making herdsman is only a fraction of -1.”

Imagine a herdsman as a parent choosing not to vaccinate a child. The great unsaid about vaccines is that if everyone in the world is vaccinated, it would make more sense for a parent not to vaccinate. This is true for two reasons. First: as more and more children are vaccinated it becomes less and less easy for viruses and bacteria to spread. Indeed, when enough people are vaccinated, these infections simply stop spreading. For example, when the polio vaccine was introduced in the United States in 1955, only 40 percent of the population was immunized, and, although the number of people paralyzed by polio declined, the virus continued to spread. However, after 70 percent of the population had been immunized, the virus stopped spreading and polio infections were eliminated from the United States.

The same is true for measles. The only difference is that measles is much more contagious than polio, so a larger percentage of people (about 95 percent) needed to be immunized. After enough people are immunized, those who aren’t can hide in the herd, protected by those around them. Second: although vaccines are safe, they aren’t perfectly safe. All vaccines have side effects, mostly pain and tenderness at the site of injection; but some side effects, such as allergic reactions, can be quite severe. By choosing not to vaccinate, one can enjoy the benefits of hiding in the herd without risking such rare but real side effects. (This is true for all vaccine-preventable diseases save one: tetanus, which is acquired from the soil, not from another person. So, even if everyone in the world is vaccinated against tetanus except for one child, the risk to that child of acquiring tetanus is the same.)

Hardin continued his essay by explaining how a rational choice can become an irrational one: “The rational herdsman concludes that the only sensible course for him to pursue is to add another animal to the herd. And another; and another.... But this is the conclusion reached by each and every rational herdsman sharing the commons. Therein is the tragedy. Each man is locked into a system that compels him to increase the herd without limit—in a world that is limited. Ruin is the destination toward which all men rush, each pursuing his own best interest in a society that believes in the freedom of the commons. Freedom in a commons brings ruin to all.”

Such is the case with vaccines. As more and more people have chosen not to vaccinate, herd immunity has broken down. Now, a choice not to get a vaccine has the benefit of avoiding rare side effects, but not the benefit of herd immunity. The studies of Salmon, Feikin, Omer, and Glanz showed that the choice not to get measles or pertussis vaccine was a choice to risk infection because not enough people were getting vaccinated.

No one has been hit harder by the loss of an immunological commons than children who can’t be vaccinated.

On October 20, 2009, Stephanie Tatel, an elementary school reading specialist in Charlottesville, Virginia, published an article on Slate.com on her efforts to find a child-care center for her son. “Last year, while searching for child care for our 2-and-a-half-year-old son, my husband and I thought we had found the perfect arrangement,” she wrote, “an experienced home day care provider whose house was an inviting den of toddler industriousness. Under her magical hand, children drifted calmly and happily from the bubble station to the fairy garden to the bunnies and the trucks, an orchestrated preschool utopia. But when I asked, ‘Are any of the children here unvaccinated?’ the hope of my son’s perfect day care experience burnt to a little crisp. As it turned out, one child had a philosophical or religious exemption—a convenient cover-all exemption that many doctors grant, no questions asked, when a parent requests one. I still do not understand how the state can allow one to attribute his or her fear of vaccines and their unproven dangers to religion or philosophy. Ordinarily I wouldn’t question others’ parenting choices. But the problem is literally one of live or don’t live. While that parent chose not to vaccinate her child for what she likely considers well-founded reasons, she is putting other children at risk. In this instance, the child at risk was my son. He has leukemia.”

Tatel knew that the unvaccinated child posed a risk to her son. “I realize that anti-vaccine sentiment has been around as long as the vaccines themselves,” she wrote. “But I wonder whether they have fully considered that the herd immunity, of which they are taking advantage, is designed to protect those who cannot be vaccinated. For now, we will hire an at-home sitter for [our son]. When he is ready to go off to school, we will have to face this issue again. Because we want him to have as ‘normal’ a life as possible, we’ll likely send him off in the bright yellow school bus and cross our fingers that the kid sitting next to him didn’t just attend a ‘chickenpox party’ over the weekend. Because what’s ‘just a case of chickenpox’ for that kid could be a matter of life or death for mine.”

Like Stephanie Tatel’s son, hundreds of thousands of people in the United States cannot be vaccinated, forced to depend on those around them to be protected.

In 1998, Hardin wrote another essay titled “Extension of ‘The Tragedy of the Commons.’” In the intervening thirty years, Hardin had witnessed increasing pollution of the air, seas, and land by “herdsmen” who had continued to “overgraze.” His summary of the situation was poignant. “Individualism is cherished because it produces freedom,” he wrote. “But the gift is conditional.”