The Emotional Epidemiology of Vaccination

by Danielle Ofri
New England Journal of Medicine

When swine flu (H1N1 influenza) first came to our attention, my patients were in a panic. Our clinic was flooded with calls and walk-in patients, all with the same question: “When will there be a vaccine?”

It was all so new then, and we didn’t have an answer. That lack of answer seemed to fuel anxiety to a fever pitch. A substantial cohort of my patients continued calling, almost on a weekly basis, to ask about the vaccine.

These, of course, were the same patients who routinely refused the seasonal flu vaccine. Each year we’d go through the same drill: I’d offer them the flu shot. I’d explain the clinical reasoning behind this recommendation. I’d strongly encourage vaccination.

“No, thanks,” they’d say. “The vaccine makes me sick.” Or “My brother had a bad reaction.” Or, simply, “I don’t do flu shots.”

The irony was painful. No matter how often I trotted out the statistics of 30,000 to 40,000 annual deaths from influenza, the patients would not be moved. So when they demanded the swine flu vaccine, I reminded them of their reluctance over the seasonal flu shot. “Oh, that’s different,” they said.

Six months passed. Flu season arrived. After repeated delays, the swine flu vaccine finally arrived in our clinic to the uniform relief of the medical staff. But my formerly desperate patients were now leery. “It’s not tested,” they said. “Everyone knows there are problems with the vaccine.” “I’m not putting that in my body.”

I was unprepared for this response, but maybe I shouldn’t have been. For weeks, in the schoolyard of my children’s elementary school, other parents had been sidling up to me, seemingly in need of validation. “You’re not giving your kids that swine flu shot, are you?” they’d say, their tone nervous, if a bit derisive.

How to explain this dramatic shift in 6 short months? It certainly isn’t related to logic or facts, since few new medical data became available during this period. It seems to reflect a sort of psychological contagion of myth and suspicion.

Just as there are patterns of infection, there seem to be patterns of emotional reaction (“emotional epidemiology”) associated with new illnesses. When 2009 H1N1 influenza was first detected, it fit a classic pattern that Priscilla Wald recently outlined in her book Contagious: It was novel and mysterious; it emerged from a teeming third-world city, and it was now making its insidious — and seemingly unstoppable — way toward the “civilized” world.

This is the story line for most headline-grabbing illnesses — HIV, Ebola virus, SARS, typhoid. These diseases capture our imagination and ignite our fears in ways that more prosaic illnesses do not. These dramatic stakes lend themselves quite naturally to thriller books and movies; Dustin Hoffman hasn’t starred in any blockbusters about emphysema or dysentery.

When the inoculum of dramatic illness is first introduced into society, the public psyche rapidly becomes infected. Almost like an IgE-mediated histamine release, there is an immediate flooding of fear, even if the illness — like Ebola — is infinitely less likely to cause death than, say, a run-in with the Second Avenue bus. This immediate fear of the unknown was what had all my patients demanding the as-yet-unproduced swine flu vaccine last spring.

As the novel disease establishes itself within society, a certain amount of emotional tolerance is created. swine flu infection waxed and waned over the summer, and my patients grew less anxious. There was, of course, no medical basis for this decreased vigilance. Unusual risk groups and atypical seasonality should, in fact, have raised concern. By late summer, the perceived mysteriousness of swine flu had receded, and the number of messages on my clinic phone followed suit.

But emotional epidemiology does not remain static. As autumn rolled around, I sensed a peeved expectation from my patients that this swine flu problem should have been solved already. The fact that it wasn’t “solved,” that the medical profession seemed somehow to be dithering, created an uneasy void. Not knowing whether to succumb to panic or to indifference, patients instead grew suspicious.

No amount of rational explanation — about the natural variety of influenza strains, about the simple issue of outbreak timing that necessitated a separate swine flu vaccine — could allay this wariness.

Similarly, reassuring fellow parents that I was indeed vaccinating my own children did little to ease their apprehension. When the New York City public school system offered free vaccinations for both students and families, there was an abysmally poor turnout. Less than one quarter of the consent forms sent home in kids’ backpacks were returned.

The dramatic shift in public sentiment over the course of the swine flu epidemic is both fascinating and frustrating. It is clear that there is a distinct emotional epidemiology and that it bears only a faint connection to the actual disease epidemiology of the virus.

We cannot combat swine flu or any influenza merely by ensuring adequate supplies of vaccine and oseltamivir. Unless the medical profession confronts the emotional epidemiology of flu vaccination with a full-court press, we run the risk of uncontrollable epidemic.

There is no doubt that we are far behind the curve in terms of public relations. Our science has not been dithering at all, but our articulation of that science has often seemed that way, from the unfortunate initial appellation of swine flu to our inability to clarify distinctions between vaccine-production issues and clinical-risk issues. Suspicion has its own contagion, and we have not been aggressive enough in countering it.

Every practicing clinician is, to some degree, an armchair epidemiologist. We register patterns of disease as they play out among our patients. We are also keen detectives of emotional epidemiology, though we often aren’t aware of this as such. Keeping tabs on the emotional epidemiology as well as the disease epidemiology, and treating both with equal urgency, are the essential clinical tools for flu season.