Future Tense

The Dramatic Push to Immunize Children Against Diphtheria Got a Boost From a Sled Dog Named Balto

With Balto’s help, New York City embarked on the first modern vaccine drive.

Posters say things like, "Immunization saves lives" and "Diphtheria strikes unprotected children."
Photo illustration by Slate. Photos by the National Archives, Library of Congress, and Getty Images Plus.

As the United States struggles to distribute and administer COVID-19 vaccines, we’re looking back at the history of vaccine rollouts in our country, including the logistical roadblocks to shots and communicating with a fearful public. The COVID vaccines have been widely shown to be safe and effective, unlike some historical examples that had significant associated risks. But what can stories of failures from the past teach us about how to fairly administer them?

On Tuesday, Feb. 16, at 1 p.m. Eastern, join Future Tense for a conversation with Atul Gawande and Helene Gayle, co-chair of the National Academies framework for vaccine distribution, about the COVID-19 vaccine rollout.

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The story of Balto, the sled dog heading up the team that brought medicine 600 miles across snowy Alaska to the children of Nome in 1925, has filtered down to us as straight Disney: a kind, brave animal overcoming great odds to help kids. But people who followed Balto’s run via newspaper coverage (or went to see him appear at a department store opening or the Cleveland zoo after he “retired”) were also cheering for a miracle of modern science. Balto and his teammates were carrying a serum for the treatment of diphtheria, called antitoxin. This particular antitoxin came all the way from New York City, where it had been incubated in the bodies of horses residing in a city-run stable dedicated to the production of medicine.

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This batch of antitoxin was not a vaccine—the children in Nome were already sick with diphtheria, the telltale gray pseudo-membranes growing over their throats. But the Balto story blew up around the time when New York City was about to start pressing for the use of a related preparation known as toxin-antitoxin to immunize as many children as possible. And so the Balto tale became a useful part of the first modern American vaccination drive—one that would establish the familiar media beats around the phenomenon for years to come.

A man in a large fur jacket crouches next to a black and white dog.
Balto with musher Gunnar Kaasen. National Institutes of Health
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The idea of a vaccine wasn’t totally new. Americans in the 1920s had a general understanding that they might need to get an emergency vaccination (whether that would be voluntary or forced upon them by authorities) in case of a local smallpox outbreak. And starting in 1911, American soldiers underwent mandatory anti-typhoid vaccination, familiarizing a new cohort of young people and their families with the concept.

But voluntary, prophylactic diphtheria immunization, of the kind promoted in the late 1920s by New York City’s Board of Health, was something new. Officials sold immunization as something that would save individual children if they came into contact with someone carrying the disease but also as a population-level safeguard—something that a 20th-century society guided by science should do as a matter of course, because it was the humane and modern thing to do.

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A series of laboratory discoveries in the late 19th century taught scientists that Corynebacterium diphtheriae, the bacillus that caused diphtheria, killed animals and people by producing a toxin. You could give animals a dose of this toxin, and they’d produce an antitoxin that, when injected into an infected human, would, in many (though not all) cases, reverse the disease in miraculous fashion. Many kids, like the ones in Nome, were saved from diphtheria by doctors who used this antitoxin as a curative measure, in the decades between its discovery and the advent of immunization. Sometimes, siblings of children with diphtheria got injections of antitoxin as a preventive.

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The sense of urgency that scientists and public health officials felt around the disease makes sense when you consider that between 1880 and 1915, thousands of children per year died from diphtheria in New York City alone. Because it wasn’t a single epidemic, it was even harder to fight—it just steadily popped up, year after year, wearing away at the population. As historian Evelynn Hammonds chronicles in her book Childhood’s Deadly Scourge, New York City waged a decadeslong campaign to control diphtheria, starting with the establishment of a program to diagnose it using bacterial analysis in 1893. A series of persistent administrators from the New York City Board of Health set up stables full of horses to produce antitoxin, undertook publicity blitzes to educate city dwellers about the disease, and looked to outside sources of funding to keep the whole thing going.

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As the years went by, the board responded to scientific developments by trying new methods of diphtheria control. German scientist Emil von Behring first successfully used a combination of diphtheria toxin and the antitoxin produced by horses to immunize against diphtheria in 1913. Also in that year, the Schick test—named for its inventor, Hungarian pediatrician Béla Schick—first allowed medical workers to see whether children had existing antibodies to diphtheria, before immunizing those who didn’t.

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Throughout the 1920s, William Park, laboratory director at the New York City Board of Health, tested the combination of the Schick test and toxin-antitoxin injections at publicly supported institutions, including foundling homes, orphan asylums, and public schools. (In using orphans in his experiments, Park participated in a practice of testing vaccines on institutionalized children that was shockingly common in the early and mid-20th century; when he tested children in the schools, parental consent was obtained.)

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Park and his colleagues were, Hammonds writes, “in one respect, incredibly lucky.” In all the years New York tested out toxin-antitoxin injections on city kids, there were no major incidents. Other places weren’t as fortunate. In 1919, five kids died in Dallas after being injected with a contaminated batch of toxin-antitoxin. In Boston, in 1924, a group of children got severe cases of the disease after injections with some toxin-antitoxin that had been frozen and thawed, separating the mixture and reactivating the toxin. (In fact, as Balto and the other teams of sled dogs raced to Nome in 1925, the mushers were delayed when they had to stop to warm up the antitoxin, as it threatened to freeze on their sleds—a problem that is the opposite of what we’re facing in 2021, in trying to transport all those Pfizer COVID-19 vaccines at subzero temperatures.) And in 1928, 12 children died in Queensland, Australia, as a result of improper storage of a multiuse bottle of toxin-antitoxin.

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By the time the Board of Health decided to make a big push to immunize as many children as possible with toxin-antitoxin, it had tried many other methods of controlling the disease. But asymptomatic carriers transmitted diphtheria without ever showing symptoms; there were many poor children in the city who were living in tenements without access to medical care; many immigrants were afraid of reporting possible cases because of legitimate fears that their children would be taken away to contagious-disease hospitals against their will.

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A girl stands on a chair surrounded by men while a man puts a button on her shirt.
New York City Health Commissioner Frank J. Monaghan pins a vaccination button on Miss Rose Gormley. Bettmann/Getty Images
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In 1929, the board’s new commissioner of health, Shirley Wynne, announced an attempt to eliminate diphtheria in NYC in two years’ time. The Board of Health used all the tools of modern publicity to plan their campaign. “This idea of diphtheria immunization had to be ‘sold’ almost in the same manner as chewing gum, a second family car, or cigarettes,” Wynne said in the Department of Health’s annual report in 1928. Billboards went up in Times Square; leaflets were sent home in electric and gas bills; more than 300 radio talks on the subject were broadcast. The effort got financial support from the Metropolitan Life Insurance Co. and the Milbank Memorial Fund, and the city’s press was fully on board, with nary a hint of skepticism to be found.

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The Board of Health also tried to increase access to the injections. “Healthmobiles”—renovated snow-removal trucks fitted out with refrigerators—toured the city, staffed with nurses who spoke the language predominant in the area they were visiting and were prepared to give persuasive talks about the benefits of immunization. Persuasion could be difficult. When looking to immunize schoolchildren, historian James Colgrove writes in a chapter-long history of the diphtheria immunization push in the 1920s in New York state, public health workers had to reassure parents that diphtheria immunization was not the same as smallpox vaccination, sending home fliers in English, Italian, and Yiddish that read: “Children are not made sick by toxin-antitoxin, as sometimes happens after smallpox vaccination.” Colgrove also found evidence of confusion among parents—and physicians—around issues like the timing of diphtheria immunization in relationship to smallpox vaccination and whether a child with eczema should be immunized. As he points out, the confusion was warranted; these were matters the Board of Health, for all its outward-facing certainty around immunization, had not yet worked out.

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Hammonds points out that the architects of the 1929 push to eradicate the disease in the city recast diphtheria as something shameful: “a visible sign of parental neglect and medical indifference.” And Colgrove cites a pamphlet distributed in upstate New York: “Hereafter, any baby or older child who suffers or dies from diphtheria will suffer or die needlessly and because someone has failed to do his or her duty.”

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But Colgrove also found a telling letter from a Queens mother, addressed to Shirley Wynne:

I have read in several of the papers that if children have not been inoculated against diphtheria it is the mother’s fault. … I would like your advice concerning my 4 small children and at least 7 or 8 other young children on this block. We have no Board of Health station in Queens Village and the nearest one is at 148 St Jamaica, which is at least a 2 hr trip (going and coming) on the trolley or bus so on account of this my children and several others have not been taken care of.

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Though official messaging targeted maternal reluctance to immunize, private physicians were perhaps an even stickier problem for officials trying to promote widespread immunization. “The health department’s collaboration with social welfare agencies in public health work was viewed skeptically by physicians,” Hammonds writes. “They saw in such projects the potential for the erosion of their client base and the specter of state medicine.” But many of the people getting immunized at free clinics would probably not have been able to afford the shots without this option. Additionally, the city gave only one of the three needed injections, referring the families to either the health department or private physicians for the other two—a measure meant to involve private physicians and direct business toward them.

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A bus has a sign on the front of it that says, "Prevent diphtheria booster toxoid."
Baltimore Department of Health

After all this work, diphtheria persisted in New York City in the early 1930s. This is perhaps because at the end of the campaign, expanded access to the vaccine for poorer families was reduced. The campaign, Hammonds concludes, strengthened “societal commitment to immunization” by attaching the practice to a sense of civic duty. At the same time, it did little to create the “institutional and social structures” needed to promote immunization on an ongoing basis. And more children were born, unimmunized, every year, ready to pick up and spread the disease. Besides, the immunity that came from toxin-antitoxin injections was not long-lasting and didn’t eliminate the “asymptomatic carrier” problem.

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But a better vaccine was in the works. In 1923, scientists in Europe figured out how to inactivate diphtheria toxin using heat and formalin (a formaldehyde derivative), creating a vaccine that was easier to produce and that conferred greater immunity. This toxoid vaccine, widely available in the United States as of the early 1940s, was what actually wiped out diphtheria in the country. This same improved method was used to produce a tetanus vaccine in 1926. And during the Roosevelt years, as more federal money went to fund public health laboratories along the New York City lines, two women—Pearl Kendrick and Grace Eldering—produced an effective vaccine for pertussis, while working for the Michigan Department of Health. Their colleague, a Black lab technician named Loney Gordon, improved the vaccine’s effectiveness further after she discovered a new strain of the bacteria.

In 1948, the diphtheria, pertussis, and tetanus vaccines were combined into the DTP shot—a landmark in childhood vaccination. It was the DTP shot that would later provoke the first wave of late-20th-century anti-vaccination activism.

Future Tense is a partnership of Slate, New America, and Arizona State University that examines emerging technologies, public policy, and society.

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