Over-reassurance is a virtually universal problem in risk communication; those in charge tend to dwell too little on what might go wrong. Vaccination has traditionally been a perfect case in point. Public health communicators try to be conscientious about telling prospective vaccinees what might go wrong, perhaps even what some critics allege might go wrong. But their heart isn’t in it. They believe in the vaccine and the vaccination process, and it shows in their tendency to over-reassure (or under-warn) about vaccine side effects.

When I started working with the CDC and other public health agencies on smallpox vaccination, I expected the usual resistance to my recommendation to stress “adverse events” more. For the most part, I didn’t find it. Lots of public health people told me their managements probably wouldn’t let them say “horrific side effects” (as I recommended) instead, but they said they’d like to. And the brochures they developed included sufficiently gruesome photos of those horrific side effects to satisfy even the most alarmist anti-vaccination activist.

It didn’t take long to figure out why. Most public health people are viscerally opposed to the smallpox vaccination program President Bush decided on in December 2002. They would have preferred the much smaller program recommended by the Advisory Committee on Immunication Practices. Or none at all. So over-reassurance about vaccination risks isn’t much of a problem this time.

The problem is over-reassurance about the risks of not getting vaccinated (or, for the society, the risks of not having a sufficient cadre of vaccinated responders) – that is, the risks of smallpox attack. The smallpox vaccine is indeed more dangerous than just about every other vaccine … but it is enormously less dangerous than smallpox. It is important to remember that vaccination isn’t just a risk. It is a precaution aimed at mitigating a greater risk.

What’s hard about the smallpox vaccination issue isn’t assessing the risk of vaccination; it’s assessing the risk of attack, especially the probability of attack. With the possible exception of the intelligence community, most of us (including public health experts) have no relevant data to assess. John’s hunch may tell him attack is virtually impossible. Sarah’s hunch may tell her it’s a real possibility. Neither John nor Sarah has much evidence.

Hunches, of course, are greatly influenced by outrage. Even when there is plenty of evidence available, outraged people often manage to distort the evidence to reach the conclusion their outrage makes them want to reach. When there is no evidence available, outrage reigns supreme. And people accustomed to judging the evidence – health experts, for instance – may well neglect to notice that this particular judgment is more hunch than professional opinion, and grounded more in their outrage than in their data. In fact, people accustomed to judging the evidence may come across as unusually confident, and unusually contemptuous of those who disagree, in cases where they have no evidence to judge. Thus, public health doctors and nurses may turn out less tolerant of those who fear a smallpox attack and want a smallpox vaccination than they ought to be … and less tolerant than they would be if they had some data rather than just outrage behind their conviction that there will be no attack and there should be no vaccination.

I want to list some of the reasons why public health people are outraged by smallpox vaccination. But first, please note that I am not arguing that a smallpox attack is likely. I don’t have any data either. I’ll even concede, without data, that attack is probably unlikely. But “unlikely” doesn’t mean zero probability. Risk assessors quantify risk by multiplying magnitude times probability. When a risk’s magnitude is high enough, even a very small probability yields a risk worth worrying about and protecting against. Let’s make a couple of wild guesses: The chance of a smallpox attack, we’ll say, is one-in-a-hundred-thousand, and such an attack would eventually kill a hundred million people worldwide. Both numbers may well be off by several orders of magnitude. But with these numbers as our straw man, the smallpox attack risk is quantitatively equivalent to a certainty of killing 1,000 people. How many prospective victims can you vaccinate with lower mortality than 1,000?

The point of this calculation is only that low-probability high-magnitude risks are hard to think clearly about. If you’re outraged about the risk, you tend to focus on its high magnitude. That’s why neighbors of Superfund sites can get bent out of joint over a one-in-a-million cancer risk. If you’re not outraged about the risk, if you’re neutral and uninvolved, you tend to focus on its low probability. Most of us, most of the time, discount low-probability risks too much, treating things that probably won’t happen as if they certainly won’t happen. That’s why disaster insurance is a tough sell. But if you go beyond neutrality, if you’re actually outraged about the precaution, then you are almost sure to discount the risk.

Public health people dismissing the risk of a smallpox attack are a little like teenagers dismissing their parents’ warnings about smoking marijuana. They hate the remedy (stay straight; vaccinate); they mistrust the source of the data (parents; intelligence experts); and so they end up treating a small but serious risk as if it were nonexistent. The analogy is far from perfect. The probability of encountering PCP-contaminated grass is probably higher and certainly more knowable than the probability of a smallpox attack; the downside of vaccination adverse events is worse than the social inconvenience and loss of pleasure entailed in Just Saying No. Still, the basics are the same. Outraged at the precaution, we underestimate the risk.

So why are so many public health people outraged at smallpox vaccination? Let me propose some possible reasons:

  1. Eradicating smallpox is high on every list of public health achievements. It is a huge source of professional pride. That pride is threatened by the homeland security experts’ claim that smallpox may not have been eradicated after all, that in its new weaponized incarnation it may threaten us now more than ever.
  2. Public health normally relies on verifiable, peer-reviewed data. Claims made without data, or with “secret data,” are taken to be the claims of charlatans. And what counts as data is narrowly defined. (Case-controlled double-blind studies are hard to come by in the intelligence arena.)
  3. The sources of the contention that the risk of attack is serious are organizations not renowned for integrity. Arguably, in fact, they are organizations whose mission requires them to lie when necessary to protect American lives. It is of course a logical fallacy to deduce from the fact that the CIA (for example) lies a lot that the CIA must be lying this time. But it is a tempting fallacy, especially when you don’t like what the CIA is saying anyway.
  4. With plenty of exceptions, public health people tend toward the political left … more so than, say, private practice physicians. When critics of smallpox vaccination claim that the program is a way of frightening the public into support for war in Iraq, or into support for repression of civil liberties at home, or for some other illiberal goal, the claim may resonate.
  5. We are all turf-defenders by nature; we cherish our sovereignty in our own domain. Vaccination is the domain of public health experts. It is rare for the recommendations of the Advisory Committee on Immunization Practices to be rejected by the President. (It’s rare for the President even to know what was recommended.) This is turf-invasion big-time.
  6. One side in the battle over vaccination was the intelligence and counter-terrorism communities, which wanted to vaccinate a lot of people. The other side was the medical and public health communities, which wanted to vaccinate very few. All else aside, solidarity with the public health profession impels the public health people who must carry out the program to dislike it; their leaders fought it hard.
  7. Nobody likes to lose. In actuality, the smallpox vaccination plan the President chose is a compromise. But just about every public health person I talk to feels like public health interests lost the policy battle to counter-terrorism interests. The counter-terrorism people probably feel they lost too.
  8. The public health profession has invested enormous effort in building the credibility of other vaccination programs, from polio to MMR. All of these vaccines have opponents, sometimes fanatical opponents. All have side effects, but generally much less serious side effects than the smallpox vaccine. There is reason to fear that smallpox vaccination could damage other vaccination efforts – especially if it backfires, if the vaccine does more harm than expected and no attack ever materializes.
  9. The public health agenda is already crowded with high-priority tasks that can’t be accomplished properly for lack of resources. Even when adequate new resources are provided for smallpox vaccination, the program still crowds out other priorities far dearer to the hearts of public health people – efforts to fight “real” killers as opposed to “theoretical” ones. And all too often smallpox vaccination becomes an unfunded or underfunded mandate.
  10. As with any low-probability high-magnitude risk, odds are there won’t be a smallpox attack. The damage done by vaccination won’t necessarily have been unnecessary, except in hindsight. But angry publics are good at hindsight. And who will be blamed for the mortality and morbidity of that unnecessary smallpox vaccination program? Beyond doubt, the public health people who (reluctantly) administered the program.
  11. Many public health people are in jobs that require them to make smallpox vaccination work as smoothly and safely as possible. They may feel they are also required to make sure enough people volunteer, which they may interpret to mean they must suppress their dislike for the program. Having to administer the program is a bitter enough pill; having to support it exacerbates the bitterness, the resentment, and the outrage.
  12. Deep in their hearts, many public health people – like many people in all walks of life – view the prospect of a bioterrorist attack on the United States with a mix of terror and rage. These emotions are hard for anyone to bear, but they may be hardest for health professionals, for whom calm is among the highest virtues. Disavowed emotions are inevitably projected onto “the other.” Anyone who expresses fear or anger about bioterrorism threatens the denial of those who cannot bear these feelings, and thus earns their contempt.

If only half of the above rationales make sense to you, they add up to a fairly strong argument. My claim is that most public health people oppose smallpox vaccination for reasons that go way beyond (or lie well beneath) the intellectual argument over the probability of attack, the probability of side effects, the efficacy of post-attack ring vaccination, etc. There is an intellectual argument here, of course, and there is a decent case to be made against vaccination. Given the huge uncertainties, it seems to me undeniable that there is also a decent case to be made in behalf of vaccination – at least voluntary vaccination of a cadre of medical and emergency responders, and probably voluntary vaccination of the general public (after appropriate screening) as well.

I don’t want to argue the merits of the case here – only to point out that many public health people are finding it hard to think objectively about the merits of the case.

Increasing their awareness of their own anti-vaccination outrage may help thoughtful public health practitioners clarify their thinking and compensate for the distortion that outrage produces. That’s part of why I wrote this “Afterthought.” But mostly it seems to me that those in charge of smallpox vaccination planning need to take the anti-vaccination outrage of the public health community into consideration. The usual strategies of outrage management all apply here: acknowledging the existence and legitimacy of the outrage; sharing credit and control; being candid; conceding (and regretting) uncertainty about the merits of the program; being accountable in the assessment of the attack risk; etc.

Developing an outrage management plan for the public health community’s outrage at smallpox vaccination isn’t an impossible task. It’s not very different from developing an outrage management plan for addressing the concerns of the opponents of any other vaccine. But it is risk communication work that needs to be done. To the best of my knowledge that is not yet happening.

Copyright © 2003 by Peter M. Sandman