On Immunity

How do you protect what you love in a world where nothing is truly safe? In On Immunity: An Inoculation, essayist Eula Biss confronts this question through an exploration that is both personal and cultural, scientific and philosophical. She weaves her own experience as a mother grappling with the decision to vaccinate her child into broader reflections on myths, medicine, and the metaphors that shape how we understand immunity.

At its heart, Biss’s argument is that immunity—both biological and social—is not an individual possession but a form of mutual responsibility. She suggests that vaccination is not simply a private choice but an ethical act that binds our bodies together in a shared ecosystem of protection and vulnerability. Her investigation questions what it means to protect our children in an age marked by distrust of institutions, fear of toxicity, and an obsession with purity. Through literary allusion, medical history, and personal narrative, Biss contends that immunity is a metaphor for how community itself functions: we survive through connection, not isolation.

Myth and the Quest for Invulnerability

Biss begins with ancient myths—the story of Achilles, the dragon-blooded hero with one vulnerable spot, and the fairy tales of parents making perilous bargains for their children’s safety. These myths mirror the parental impulse to protect a child from every harm. But as Biss learns after her son’s birth, absolute safety is impossible. Immunity, like mortality, carries its own vulnerabilities. “Immunity is a myth,” she writes; it can never be complete. The modern vaccine, she realizes, is our attempt to bargain with fate—a measured risk meant to guard against far greater dangers.

Fear, Trust, and the Body Politic

Biss situates vaccine anxieties within an atmosphere of cultural distrust—corrupt corporations, wavering governments, and sensationalist media have eroded confidence in authority. When public trust wavers, she observes, people turn inward, seeking control through self-curation: organic food, toxin-free homes, and selective vaccination. But this pursuit of purity, she argues, mirrors older systems of exclusion, echoing how societies once associated disease with filth and moral corruption. As she puts it, our modern obsession with “toxicity” has replaced the moral panic of “filth theory.” Both isolate the self from an imagined contaminating other.

The Collective Body and Moral Obligation

Central to Biss’s argument is the concept of herd immunity—a scientific reality that also serves as an ethical metaphor. When enough individuals are vaccinated, a community becomes collectively resistant to disease, protecting even those who cannot be vaccinated. Biss views this as a modern form of altruism, “a banking of immunity,” where each person’s participation strengthens the social whole. This shared protection depends on trust and mutual responsibility, challenging the myth of individual autonomy that dominates Western thinking. For her, herd immunity embodies Kierkegaard’s idea that loving one’s neighbor is both moral and literal: our health is linked to the bodies around us.

Immunity as Metaphor and Mirror

Throughout the book, Biss examines how metaphors shape our perception of medicine. She finds that when we describe vaccination as a “shot” or “jab,” we invoke imagery of violence and invasion. When we compare disease to war, we see our bodies as battlefields rather than ecosystems. Instead, she proposes metaphors of interdependence—gardens, webs, and shared bodies—that better express the cooperative nature of our immune systems and societies. Drawing from immunologists, she notes that the cells within our immune systems communicate more like educators or diplomats than soldiers. This reframing helps us see immunity not as self-defense but as relationship and adaptation.

The Moral Ecology of Modern Life

Biss’s exploration expands beyond immunology into ecology and ethics. She draws parallels to environmentalist Rachel Carson’s Silent Spring, which revealed how the health of humans and ecosystems are intertwined. While Carson fought the indiscriminate use of DDT, Biss critiques indiscriminate distrust of medicine. Both, she suggests, stem from fears of contamination and a yearning for control in a complex world. Yet Biss finds hope in the messy interdependence of life—our bodies are already “polluted” with microbes and chemicals, but also full of mutual life. To be alive is to be porous, shared, and dependent.

Why It Matters

By the end of On Immunity, Biss has transformed a debate often reduced to science versus skepticism into a meditation on trust, collective responsibility, and the boundaries of self. Her argument matters because it illuminates not only why we should vaccinate, but also how we live with one another in an age of fear and fragmentation. In a society that prizes independence, she reminds us that true safety arises from connection. Immunity, like community, is only as strong as our willingness to share it.

Becoming a parent, Eula Biss discovers, transforms the abstract into the urgent. Fear becomes visceral, ticking like a heartbeat. She opens her story with myths her physician father told her as a child—tales where immortality comes at a price, like Achilles dipped in the Styx or the warrior bathed in dragon’s blood. In these stories, safety is always incomplete—each hero bears a fatal weak spot. This, for Biss, is the parable of modern parenthood: no amount of precaution can shield a child entirely from harm.

Parenthood as a Negotiation with Fate

As a mother navigating a new world of risks—pandemic warnings, toxic household chemicals, anxious parenting handbooks—Biss finds that the impulse to protect often becomes a kind of helpless bargaining. Parents trade invisible dangers: give my child fever for one night so he may not face a fatal illness later. She and her husband jokingly frame this as a “game” of impossible parental decisions. Through humor, she exposes the cruel arithmetic of love under uncertainty.

From Myth to Modern Anxiety

The myths of childhood feed into twenty-first-century fears. When her son is born during the 2009 H1N1 influenza pandemic, Biss’s circles of mothers begin debating whether the hastily developed vaccine might be as dangerous as the disease itself. In these conversations, trust fractures easily—media sensationalism, the incompetence of government, and the presumed greed of pharmaceutical companies feed suspicion. “It was not a good season for trust,” she observes dryly, noting that the aftermath of war and financial crisis had already seeded cynicism. The cultural atmosphere of doubt, she suggests, infects motherhood as surely as any virus.

Safety in an Unsafe World

Biss redefines protection not as sealing off the self, but as entering into reciprocal obligation. The fantasy of perfect safety—the “pure body,” free from contamination—is both illusion and danger. In seeking this purity, we isolate ourselves. The vaccination choice, she argues, becomes a moral test: do we protect only our own child, or do we contribute to the shield that protects others’ children too? Her question echoes beyond medicine—it challenges the individualism that underpins much of American life.

The Heroic Vulnerability of Parenthood

In the end, what Biss finds is not control but acceptance. Like the mythical mothers who dipped their children into rivers or bargained with enchantresses, she can only act through imperfect means. Vaccination, she concludes, is less an assertion of invulnerability than a humble recognition of our shared fragility—a small gesture of faith that life depends not on mastery but on mutual care.

Words, Biss reminds us, are our immune system’s most powerful prosthetics. The metaphors we use to describe disease shape not only how we understand it but how we feel it. When Americans call vaccines a “shot” or the British a “jab,” we turn prevention into violence. When politicians declare a “war on disease,” we position our own bodies as battlegrounds. These linguistic choices matter—they determine whether we see medicine as invasion or communion.

From Contamination to Connection

Historically, vaccination was viewed through metaphors of moral pollution. In the nineteenth century, priests compared it to injecting sin—a literal corruption of blood. Some called the vaccine scar the “mark of the beast.” Today’s fears—of mercury, aluminum, “toxins”—revive that language in secular form. Anti-vaccine culture, Biss argues, inherits this anxiety about purity, shifting it from spiritual to chemical contamination. Our “witches’ brew” of mercury and squalene echoes the fears of vampires and contagion that haunted Victorian science.

Vampires, Viruses, and Violation

Biss’s fascination with vampires—both literary and cultural—serves as metaphor for the paradox of modern medicine. In Bram Stoker’s Dracula, contagion spreads through blood and desire, dramatizing fears of impurity and invasion. Like vaccination, vampirism blurs the boundary between self and other, life and death. Both require penetration, exchange, and transformation. Yet in modern retellings, vampires become conflicted moral beings—a reflection, Biss suggests, of our evolving relationship to medicine: our longing to heal without harm, to take life from one another without guilt.

Rethinking the Body

The immune system itself, she discovers, is laden with metaphors. Scientists describe “killer” cells and “memory” cells, “invaders” and “defenders.” But this militarized language, anthropologist Emily Martin notes, blinds us to the immune system’s diplomacy—its ability to teach, learn, and coexist. Biss proposes gentler metaphors: the body as garden, as classroom, as polyphonic choir. When we adopt new metaphors, she writes, we not only heal our vocabulary but reimagine our relationships—to each other, to medicine, and to the unseen life within us.

(In a similar spirit, Susan Sontag’s Illness as Metaphor likewise warns that militarized imagery of disease—battles, attacks, victories—can wound the imagination as deeply as bodies. Biss extends this insight into the age of vaccines.)

Who is public health really for? Biss confronts this uncomfortable question when her pediatrician casually assures her that the hepatitis B vaccine is for “the inner city”—for “drug addicts and prostitutes,” not people like her. In this moment, she realizes how privilege distorts the perception of risk. Her relief at being exempted from a “poor person’s disease” quickly turns to shame. The illusion that diseases belong to other people—immigrants, the poor, the unclean—has haunted public health from smallpox to HIV and now to vaccines.

The Historical Burden of Inequality

Biss recounts how nineteenth-century vaccination campaigns often exploited the bodies of the vulnerable. Poor and minority communities were vaccinated at gunpoint during smallpox outbreaks, absorbing the risk so that the privileged could remain safe. By contrast, today’s vaccination hesitancy tends to cluster among the affluent—the very people historically shielded from risk. This, she argues, is an inversion of moral responsibility: those most protected from disease now opt out of collective protection, endangering those with less choice or access.

Privilege, Danger, and the “Pure” Child

Biss points to data showing that unvaccinated children in America are disproportionately white, wealthy, and well-educated, while those merely “undervaccinated” tend to be poor and Black. The unvaccinated, she writes, imagine themselves vulnerable but are in fact dangerous—their children can carry disease to infants too young for immunity. This moral contradiction exposes what she calls the “illusion of innocence”—the belief that purity (of body or class) confers safety. The privileged, she concludes, are not purely vulnerable; they are also vectors in an interdependent world.

Medicine, Capital, and Trust

The book repeatedly asks whether medicine can exist apart from capitalism. From nineteenth-century doctors selling “heroic” cures to modern pharmaceutical profiteering, Biss traces the tension between healing and commerce. Yet she insists that cynicism cannot be our only posture. To reject public medicine entirely, she warns, is to reject the very notion of public good. Trust, like herd immunity, is a collective resource—fragile but essential. Without it, both medicine and democracy decay.

By drawing this historical and ethical arc, Biss reframes vaccination as an act of equality: protection that transcends class. Immunity, she argues, can invert privilege—granting the wealthy not exemption from risk, but participation in the defense of those most at risk.

Fear of contamination, Biss argues, is one of modern America’s defining pathologies. Where earlier centuries obsessed over filth, we now speak of toxins. Hand sanitizer, antibacterial soap, organic produce, and “natural” remedies promise to cleanse us from invisible threats. Yet these purifications rarely make us safer—they deepen our estrangement from the natural world and from each other. To fear pollution, Biss observes, is to misunderstand what it means to live in ecological continuity with the planet.

From Filth Theory to Toxicity Theory

In the nineteenth century, disease was blamed on filth—on moral and physical decadence. Reformers shuttered windows against “bad air” and built sanitary cities. Clean water and sewage control indeed saved lives, but the association of disease with impurity stigmatized the poor. Today, purity has gone chemical rather than moral: middle-class consumers equate wellness with detox diets, paraben-free lotions, and mercury-free vaccines. As Biss quips, we shutter our modern windows with air purifiers and bottled water instead of faith.

Rachel Carson and the Poisoned World

Biss revisits Rachel Carson’s Silent Spring to remind us that environmental fear can be both necessary and misplaced. Carson exaggerated some dangers of DDT, yet her warnings awakened ecological consciousness. Biss argues that we’ve inherited not only Carson’s ethics but also her anxiety—a fixation on unseen pollutants that mirrors our mistrust of vaccines. In both cases, the fear of invisible poisons can eclipse their measured understanding. The true lesson, she says, is not to flee nature’s corruption but to accept our permeability: our bodies are “as polluted as the world.”

The Fantasy of Cleanliness

Plastic-free mattresses, antibacterial wipes, and vegan supplements, Biss notes, often become secular sacraments of righteousness. She recalls sobbing over her infant’s crib mattress after learning about industrial chemicals in plastics—an emblem of maternal helplessness. But her father, a doctor, reminds her: the world can’t be purified. The immune system, like democratic society, relies on regulation, not eradication. Over-cleaning and deregulation both threaten the delicate balance that protects us. The body, she concludes, thrives not by isolation but by negotiation with its environment.

Fear, once a tool for survival, becomes self-defeating when absolute. Biss invites you to imagine trust not as blindness but as biological wisdom—the capacity to coexist with danger, just as our bodies coexist with the microbes that make us whole.

Few scientific concepts better capture moral interdependence than herd immunity. For Biss, it becomes the book’s central metaphor—a living illustration of how societies depend on invisible trust. When enough people are vaccinated, disease cannot spread; even the unprotected are shielded. This principle, both fragile and profound, transforms biology into ethics: our skin is not the boundary of responsibility.

From Blood Banks to Immunity Banks

After donating her newborn son’s cord blood to a public bank, Biss imagines vaccination as a similar deposit—an investment in the health of strangers. Like Kierkegaard’s “works of love,” immunity is known not by belief but by its fruits. “We owe each other our bodies,” Biss reflects, recalling her father, an O-negative “universal donor.” In giving blood, he embodied the principle that private resources (even blood) can serve the common good. Vaccination, in this light, becomes a communal tithe rather than a corporate transaction.

The Fragility of Trust

Yet herd immunity relies on belief as much as biology. One skeptical mother tells Biss that herd immunity “only applies to cows.” The phrase itself, Biss notes, grates against American individualism: no one wants to belong to a herd. She proposes instead the metaphor of the hive—a model of intelligent interdependence. Like bees, humans thrive through cooperation and shared vigilance. The breakdown of that trust endangers both species and societies.

Science as a Collective Act

Biss also likens herd immunity to the scientific process itself: knowledge is not produced by solitary geniuses but by a swarm of collective inquiry. Her account of the 2003 SARS investigation—ten research teams collaborating across continents to identify a new virus—illustrates this “wisdom of crowds.” Science, she concludes, is the mind of the herd at its best: a community guided by evidence rather than paranoia.

Herd immunity, then, is a social covenant written in our cells. It asks each of us to accept small vulnerability for the sake of greater resilience. Its true challenge, Biss insists, is not scientific but moral—to believe that we owe our safety to strangers as much as to ourselves.

In her closing chapters, Biss pushes beyond health into philosophy. What, she asks, is the boundary between our own bodies and the world’s? Modern science, she shows, is slowly dismantling the notion of the body as fortress. We are microbial mosaics—more bacterial cells than human ones. The immune system, once imagined as an army defending the self, now appears as a complex network negotiating with other life forms. This understanding dissolves the binary between self and nonself, purity and pollution, immunity and community.

The Danger Model

Drawing on immunologist Polly Matzinger’s “Danger Model,” Biss describes immunity as an ethics of discernment: the body responds not to what is foreign, but to what is harmful. Harmless strangers—microbes, fetuses, food—are tolerated, even welcomed. This shift reframes immunity as relational intelligence, not hostility. “The body,” Biss writes, “is not a battlefield but a garden,” where cooperation and dialogue replace aggression. To cultivate health is therefore to cultivate tolerance—of bacteria, of others, of uncertainty itself.

From the Body to the Body Politic

Extending this metaphor to society, Biss invokes Queen Elizabeth I’s proclamation that she possessed both a natural and a political body. Every citizen, she argues, lives within a similar duality: private freedom and public belonging. Vaccination dramatizes this overlap—the needle pierces both skins at once. Our individuality depends on collective health. When we reject connection under the illusion of independence, we replicate disease’s logic of isolation.

Cultivating the Shared Garden

In one of her most hopeful conclusions, Biss imagines community itself as a “microbial garden.” Diversity strengthens it; monoculture weakens it. Just as our internal microbiomes require balance, so does our civic life. “We are each other’s environment,” she writes. Trust is the soil; participation the water; knowledge the sunlight. The cure for fear is not purity but cultivation. Immunity, like love, is maintenance work—endless, imperfect, essential.

By blending biology, literature, and moral vision, Biss closes where she began—with myth transformed into responsibility. To be human, she shows, is to live vulnerably among others, dependent on the invisible kindness of their bodies. Immunity, finally, is both fact and metaphor for how we survive one another.