On Immunity : An Inoculation (9781555973278) (3 page)

D
EEP WITHIN EVERY MAN there lies the dread of being alone in the world, forgotten by God, overlooked among the tremendous household of millions upon millions,” Søren Kierkegaard wrote in his journal in 1847. That was the year he finished
Works of Love
, in which he insists that love is known not through words, but only “by its fruits.”

I read the first fifty pages of
Works of Love
in college before giving it up out of exhaustion. In those pages Kierkegaard unfolds the commandment “You shall love your neighbor as yourself,” parsing it almost word by word, so that after exploring the nature of love he asks what is meant by “as yourself,” and then what is meant by “your neighbor,” and then what is meant by “you shall.” Overwhelmed, I stopped reading shortly after Kierkegaard asked, “
Who, then, is one’s neighbor?,”
which he answered, in part, with, “
Neighbor
is what philosophers would call the
other
, that by which the selfishness in self-love is to be tested.” I had read enough at that point to be troubled by the idea that one must enact one’s beliefs, and perhaps even embody them.

From somewhere deep in my childhood I can remember my father explaining with enthusiasm the principle behind the Doppler effect as an ambulance sped past our car. When we watched the sun set over the river where we lived he described Rayleigh scattering, the removal of the shorter wavelengths of light by the atmosphere that results in reddish clouds and grass that looks more intensely green at dusk. In the woods he dissected an owl pellet for me, and reassembled from it the tiny skeleton of a mouse. My father marveled at the natural world far more often than he talked about the human body, but blood types were a subject on which he spoke with some passion.

People with the blood type O negative, he explained, can only receive in transfusion blood that is O negative, but people with O-negative blood can give blood to people of any other type. That’s why a person with Type O negative is known as a “universal donor.” My father would then reveal that his blood type was O negative, that he himself was a universal donor. He gave blood, my father explained, as often as he was allowed because blood of his type was always in demand for emergency transfusions. I suspect my father may have already known then what I would only discover later—that my blood, too, is Type O negative.

I understood the universal donor more as an ethic than as a medical concept long before I knew my own blood type. But I did not yet think of that ethic as an ingenious filtering of my father’s Catholicism through his medical training. I was not raised in the Church and I never took communion, so I was not reminded of Jesus offering his blood that we all might live when my father spoke of the universal donor. But I believed, even then, that we owe each other our bodies.

Every time my father went out in a boat, for my entire childhood, he took a life preserver with his name and “Organ Donor” printed hugely on it in permanent ink. It was a joke in which he believed quite sincerely. When he taught me to drive, he gave me this advice from his own father: you are responsible not just for the car you are driving, but also for the car ahead of you and the car behind you. Learning to drive all three cars was daunting, and inspired an occasional paralysis that plagues my driving to this day, but when I earned my license I signed my name under Organ Donor.

The very first decision I made for my son, a decision enacted within moments of his body coming free of mine, was the donation of his umbilical cord blood to a public bank. At thirty, I had only donated blood once, back in college when I was reading Kierkegaard. I wanted my son to start his life with a credit to the bank, not the debt I already felt. And this was before I, a universal donor, would become the sole recipient of two units of blood in transfusion after my son’s birth—blood of the most precious type, drawn from a public bank.

If we imagine the action of a vaccine not just in terms of how it affects a single body, but also in terms of how it affects the collective body of a community, it is fair to think of vaccination as a kind of banking of immunity. Contributions to this bank are donations to those who cannot or will not be protected by their own immunity. This is the principle of
herd immunity
, and it is through herd immunity that mass vaccination becomes far more effective than individual vaccination.

Any given vaccine can fail to produce immunity in an individual, and some vaccines, like the influenza vaccine, are less effective than others. But when enough people are vaccinated with even a relatively ineffective vaccine, viruses have trouble moving from host to host and cease to spread, sparing both the unvaccinated and those in whom vaccination has not produced immunity. This is why the chances of contracting measles can be higher for a vaccinated person living in a largely unvaccinated community than they are for an unvaccinated person living in a largely vaccinated community.

The unvaccinated person is protected by the bodies around her, bodies through which disease is not circulating. But a vaccinated person surrounded by bodies that host disease is left vulnerable to vaccine failure or fading immunity. We are protected not so much by our own skin, but by what is beyond it. The boundaries between our bodies begin to dissolve here. Donations of blood and organs move between us, exiting one body and entering another, and so too with immunity, which is a common trust as much as it is a private account. Those of us who draw on collective immunity owe our health to our neighbors.

When my son was six months old, at the peak of the H1N1 flu pandemic, another mother told me that she did not believe in herd immunity. It was only a theory, she said, and one that applied mainly to cows. That herd immunity was subject to belief had not yet occurred to me, though there is clearly something of the occult in the idea of an invisible cloak of protection cast over the entire population.

Aware that I did not fully understand the mechanism behind this magic, I searched the university library for articles about herd immunity. As early as 1840, I learned, a doctor observed that vaccinating only part of a population against smallpox could arrest an epidemic in full. This indirect protection from disease could also be observed, temporarily, after large numbers of people acquired natural immunity from infection during an epidemic. In the era before vaccination against childhood diseases like measles, epidemics tended to come in waves followed by lulls during which the number of new children who had not been made immune by infection crept toward some crucial, but unknown, proportion of the population. Herd immunity, an observable phenomenon, now seems implausible only if we think of our bodies as inherently disconnected from other bodies. Which, of course, we do.

The very expression
herd immunity
suggests that we are cattle, waiting, perhaps, to be sent to slaughter. And it invites an unfortunate association with the term
herd mentality
, a stampede toward stupidity. The herd, we assume, is foolish. Those of us who eschew the herd mentality tend to prefer a frontier mentality in which we imagine our bodies as isolated homesteads that we tend either well or badly. The health of the homestead next to ours does not affect us, this thinking suggests, so long as ours is well tended.

If we were to exchange the metaphor of the herd for a hive, perhaps the concept of shared immunity might be more appealing. Honeybees are matriarchal, environmental do-gooders who also happen to be entirely interdependent. The health of any individual bee, as we know from the recent epidemic of colony collapse, depends on the health of the hive. In
The Wisdom of Crowds
, journalist James Surowiecki details the sophisticated scouting and reporting methods honeybees use to gather nectar. The cooperative work of bees, Surowiecki suggests, is an example of the kind of collective problem solving our own society depends on.

While there are many well-documented instances of crowds making bad decisions—lynching comes to mind—Surowiecki observes that large groups routinely solve complex problems that evade individuals. Groups of people, if they are sufficiently diverse and free to disagree, can provide us with thinking superior to any one expert’s. Groups can locate lost submarines, predict the stock market, and reveal the cause of a new disease. In March of 2003, after a mysterious respiratory disease killed five people in China, the World Health Organization arranged a collaboration between research laboratories in ten different countries to identify the cause of what would come to be known as SARS. The labs, themselves made up of teams, worked together, sharing information and debating their results in daily conferences. By April, they had isolated the novel virus responsible for the disease. No one person had been in charge of the process, and no one person could claim credit for the discovery. Science, Surowiecki reminds us, is “a profoundly collective enterprise.” It is a product of the herd.

M
Y SON IS FULLY VACCINATED, but there is one immunization on the standard schedule that he did not receive on time. This was meant to be his very first shot, the hep B administered to most babies immediately after birth. In the months before my son was born, while I was teaching at the university and hauling a used crib through the snow and moving bookshelves to make room for the crib, I began spending my evenings reading articles about immunization. I was already aware, before I became pregnant, of some fears around vaccination. But I was not prepared for the labyrinthine network of interlocking anxieties I would discover during my pregnancy, the proliferation of hypotheses, the minutiae of additives, the diversity of ideologies.

Finding that the reach of my subject had far exceeded the limits of my late-night research by the time my baby was due, I visited the pediatrician I had chosen to be my son’s doctor. A number of friends had offered his name when I asked for a recommendation, and so had my midwife, who referred to him as “left of center.” When I asked the pediatrician what the purpose of the hep B vaccine was, he answered, “That’s a very good question,” in a tone that I understood to mean this was a question he relished answering. Hep B was a vaccine for the inner city, he told me, designed to protect the babies of drug addicts and prostitutes. It was not something, he assured me, that people like me needed to worry about.

All that this doctor knew of me then was what he could see. He assumed, correctly, that I did not live in the inner city. It did not occur to me to clarify for the doctor that although I live in the outer city of Chicago, my neighborhood is very much like what some people mean when they use the term
inner city.
In retrospect, I am ashamed by how little of his racial code I registered. Relieved to be told that this vaccine was not for people like me, I failed to consider what exactly that meant.

The belief that public health measures are not intended for people like us is widely held by many people like me. Public health, we assume, is for people with less—less education, less-healthy habits, less access to quality health care, less time and money. I have heard mothers of my class suggest, for instance, that the standard childhood immunization schedule groups together multiple shots because poor mothers will not visit the doctor frequently enough to get the twenty-six recommended shots separately. No matter that any mother, myself included, might find so many visits daunting.
That
, we seem to be saying of the standard schedule,
is for people like them.

In an article for
Mothering
magazine, the journalist Jennifer Margulis expresses outrage that newborn infants are routinely vaccinated against hep B and wonders why she was encouraged to vaccinate her daughter “against a sexually transmitted disease she had no chance of catching.” Hep B is transmitted not only by sex, but through bodily fluids, so the most common way that infants contract hep B is from their mothers. Babies born to women who are infected with hep B—and mothers can carry the virus without their knowledge—will almost certainly be infected if they are not vaccinated within twelve hours of birth. The virus can also be passed through close contact between children, and people of any age can carry it without symptoms. Like human papillomavirus and a number of other viruses, hep B is a carcinogen, and it is most likely to cause cancer in people who contract it when they are young.

One of the mysteries of hep B immunization is that vaccinating only “high risk” groups, which was the original public health strategy, did not bring down rates of infection. When the vaccine was introduced in 1981, it was recommended for prisoners, health care workers, gay men, and IV drug users. But rates of hep B infection remained unchanged until the vaccine was recommended for all newborns a decade later. Only mass vaccination brought down the rates of infection, and it has now virtually eliminated the disease in children.

The concept of a “risk group,” Susan Sontag writes, “revives the archaic idea of a tainted community that illness has judged.” Risk, in the case of hep B, turns out to be a rather complicated assessment. There is risk in having sex with just one partner, or traveling through the birth canal. In many cases, the source of infection is never known. I decided, before I knew how much blood I would lose in childbirth, that I did not want my son to be vaccinated against hep B. I did not belong to a risk group at the moment he was born, but by the time I put him to my breast I had received a blood transfusion and my status had changed.

When the last nationwide smallpox epidemic began in 1898, some people believed that whites were not susceptible to the disease. It was called “Nigger itch,” or, where it was associated with immigrants, “Italian itch” or “Mexican bump.” When smallpox broke out in New York City, police officers were sent to help enforce the vaccination of Italian and Irish immigrants in the tenements. And when smallpox arrived in Middlesboro, Kentucky, everyone in the black section of town who resisted vaccination was vaccinated at gunpoint. These campaigns did limit the spread of the disease, but all the risk of vaccination, which at that time could lead to infection with tetanus and other diseases, was absorbed by the most vulnerable groups. The poor were enlisted in the protection of the privileged.