How Big is the Risk of H1N1 ("Swine") Flu?
Putting risks in analytic and ethical perspective
21 Oct 2009 in Regulatory Science, Regulatory Policy
The Washington Post's Rob Stein reports some interesting information useful for estimating the magnitude of this risk. Elsewhere in today's Post, others argue that people have a moral obligation to be vaccinated. The moral argument hinges on the fact that vaccination reduces risks to others, but this is complicated by the fact that most of the "others" in question are people who choose not to be vaccinated.
First, the analytic perspective. Stein reports the following statistics:
Although it remains unclear how frequently the virus makes people seriously ill, recent reports from Mexico, Canada, the United States, Australia and New Zealand indicate that perhaps 1 percent of patients who get infected require hospitalization. Between 12 to 30 percent of those hospitalized need intensive care, and 15 to 40 percent of those in intensive care die.\
These figures are imprecise, and even if they were certain it's not clear how to interpret them because they are a composite from multiple nations with very different health care systems. With that caveat in mind, the mortality risk from H1N1 (swine) flu for those known to be infected with the virus is between one in 10,000 and one in 1,000. Assuming that cases not requiring hospitalization are never fatal and that all fatalities occur in hospital inensive care units, this risk is calculated as follows:
- % hospitalization | + diagnosis x % ICU | hospitalization x % who die | ICU = mortality rate | + diagnosis.
- 1% x {12% to 30%} x {15% to 40%} = 0.018% to 0.12%.
If these figures were true, the risk would be barely high enough to warrant regulation by the Occupational Safety and Health Administration. (OSHA's threshold for a "significant frisk" is one in 1,000.) But the range overstates the risk of death from H1N1. It begins with the portion of the population that is known to be infected by the H1N1 virus. Only people with symptoms would have sought medical care. We do not know if that is 10%, 1%, 1/10th of 1%, or 1/100th of 1% of the infected population, but whatever it is, when multiplied by the mortality risk calculated above, it falls below the 10-3 threshold. The risk is probably too low to warrant attention by the US Environmental Protection Agency, even if the EPA had authority to act (which it lacks), because EPA's implied definition of a de minimis risk is one that is between 10-4 (one in 10,000) and 10-6 (one in one million).
In Virginia, the proportion of emergency room and urgent care visits involve people experiencing influenza-like illness (ILI) exceeds 4.5% in most counties for the week ending October 10. (Higher rates were observed in earlier weeks.) Positive laboratory isolates for H1N1 spiked in June and declined, but in recent weeks have risen again. Still, the highest percentage of patients presenting with ILI who have documented H1N1 infection has never exceeded 7%. Multiplying these pecentages together, the two peaks in the incidence of H1N1 infection among persons seeking ER or urgent care in Virginia were about 0.1% for the week ending June 20th and 0.2% for the week of October 10. What makes this flu outbreak different is that healthy young people, not the elderly, appear to be most affected (see the green line in this chart).
Recognizing that the incidence rates reported above are probably upwardly biased, we can take a stab at addressing a crucial question: It is rational for an individual to choose to be vaccinated to avoid the consequences of H1N1 infection? The economics literature is rich with empirical studies of how much people are willing to pay to avoid mortality risks in this range. Virtually the entire spectrum of empirical estimates is encompassed by the range $1 to $10. (There is a positive externality associated with vaccination, but it is probably a small fraction of these figures.)
The upper-bound of this range is less than the cost of the vaccine, so why would people choose to be vaccinated anyway? There are several possible reasons:
- People believe that the risk is larger than it really is. This is entirely plausible, as government officials have not been shy about exaggerating the magnitude of the risk to motivate people to be vaccinated. Exaggeration works so long as the public does not learn about it. If word gets out, the public begins to distrust officials and discount official statements, even when they are true.
- People believe that they are more exposed to this risk than average. Health care workers and teachers both qualify. Indeed, there are many occupations (flight attendants, restaurant employees, etc.) in which there is regular contact with a lot of people. State health departments are in charge of setting priorities for vaccination, but the government's prioritization scheme seems not to be based on this factor. Still, there is no good reason to behave as if the average risk applies to you if you believe that your risk is above average. Conversely, people who reasonably believe that their risk is below average are among the most difficult to persuade to accept vaccination. What would be nice to know empirically is whether a Lake Wobegone Syndrome exists in which the bast majority of people mistakenly believe that they are above average.
- People are highly risk averse with respect to this particular risk. It is possible that people fear dying from influenza more than dying from other causes. However, there is little or no evidence that people dread influenza more than, say, dying from cancer or falling from a tall building or in a fire.
- People choose vaccination to protect others as well as themselves. The federal Centers for Disease Control and State health departments have placed them at the top of the queue for obtaining vaccination. Pregnant women are rationally precautionary with respect to both real and hypothetical rsks to their unborn babies, so little persuasion is likely to be necessary except in cases where an ideological or religious objection to vaccination is present
- People choose vaccination as an expression of altruism or civic duty. These are rational grounds for action even if appears that they do not fit in the economic model. They do, of course, because the economic model is not about dollars and cents; it is about explaining why people make the choices they do, and choices that are not motivated by monetary considerations nevertheless have consequences that can be expressed in monetary terms.
Now, the ethical perspective.
Elsewhere in the Post are commentaries by ten members of the Post/Newsweek's "On Faith" panel. Four belong to minor groups within the 158 million strong US Christian community. One is Anglican (2.3 million), one is Seventh-day Adventist (2.2 million); and two are United Church of Christ (1.2 million). Of the other six, two are Jews (5 million in the US), three are atheists, and one is a Wiccan.
How did panelists address the moral and ethical issue of vaccination against H1N1 (swine) flu? The four questions posed to them are:
- Is it ethical to say no to this or any vaccine?
- Are there valid religious reasons to accept or decline a vaccine?
- Will you get a swine flu shot?
- Will your children?
Predictably, the atheists agreed that there is no religious ground for refusing vaccination. Surprisingly, they also agreed that opposition to vaccination is a characteristic shared by religious believers. None of the panel members with religious views opposed vaccination on religious grounds. Religious reasons also were not reported in in recent opinion polling, which suggests that religious objections to vaccination are too rare to measure. Wher we could find evidence, it was most prevalent among nonbelievers residing in wealthy, politically liberal precincts.
In Southern California, for example, the Los Angeles Times collected data showing that rates of exemption from State-mandated vaccination were highest on the Westside, the Palos Verdes Peninsula, and the central Orange County coast (map) -- all liberal enclaves:
At Ocean Charter School in Del Rey, near Marina del Rey, 40% of kindergartners entering school last fall and 58% entering the previous year were exempted from vaccines, the highest rates in the Los Angeles Unified School District.
Administrators at the school said the numbers did not surprise them. The nontraditional curriculum, they said, draws well-educated parents who tend to be skeptical of mainstream beliefs.
"They question traditional knowledge and feel empowered to make their own decisions for their families, not deferring to traditional wisdom," said Assistant Director Kristy Mack-Fett.
To obtain an exemption in California, a parent need only assert that vaccination is "contrary to my beliefs." Religion is not a factor.
Atheist author Susan Jacoby is one who emphasized these purported religious objections to vaccination, which she calls "bogus." In her view, vaccination becomes a moral obligation if the State mandates it. Because the H1N1 vaccine is not mandated, Jacoby concedes that it is permissible to decline it: "I don't think that there is any absolute ethical mandate to get a flu shot: I simply consider it prudent."
Jacoby's views are thus primarily utilitarianism, but blended with appeals to civic duty and a certain formal legalism. If reduced to a principle, freedom to choose not to vaccinate is derived from the State's decision not to make them mandatory. A review of her other commentaries indicates that she does not hold this view consistently. Sometimes, Jacoby writes approvingly of State power over individual decision-making, but at other times she criticizes it rather harshly. It would be interesting to learn how she would interpret the Southern California data.
Atheist Paula Kirby also rejects any religious ground for declining H1N1 vaccination. She places her faith in what she calls "scientific medicine," which she distinguishes in both substance and intent from medicine as used to be practiced, and says that opposition to vaccination is attributable to ignorance.
Vaccines are a matter of public health. If we refuse to be vaccinated it is not just ourselves we are endangering, but our children, our elderly parents, our neighbours, our fellow passengers on the bus and the pregnant woman in the queue at the supermarket.
Our moral obligation is so abundantly clear that surely even religion cannot prevent us from seeing it.
This moral obligation is so abundantly clear that Kirby does not bother making a moral argument in support of it.
Secularist Herb Silverman denies that religion can provide a moral ground for refusing vaccination, but says that adults have ethical obligations with respect to community health risks:
I think an adult should have maximum decision-making freedom on issues that involve him or her, alone. However, since all viruses are contagious, ethical considerations demand taking into account how declining a vaccine may also affect others.
Silverman does not flesh out these ethical considerations except to note obvious cases where it is violated -- for example, parents who deny medical care to a child with appendicitis. He does not acknowledge, however, that even this example lies outside the bounds of communicable disease, a boundary that Silverman himself defined as relevant to addressing the ethical issues of vaccination. He is especially critical of fellow liberal and atheist Bill Maher, who oppose vaccination.
With regard to whether he will get the H1N1 vaccination, Silverman says the answer is an "unequivocal 'probably'."
Then again, it's conceivable that I could change my mind tomorrow. One certainty is that I plan to base my decision on what I view as the best available evidence at the time--the scientific, not talk show, evidence.
Like others whose views are not founded on religion, Silverman's position is ultimately utilitarian. He will weigh the costs and benefits; he will decide how much weight to put on the risks others may experience if he declines vaccination; and he will judge in ethical terms the decisions of others based whether they conform, either in result or in method of decision-making, to his own.
The religious writers are unsurprisingly more respectful of the notion that religion has something to say on the question, and their views display varying amounts of moral reasoning.
Starhawk, "a prominent voice in modern Wiccan spirituality" and self-described Pagan, says that vaccines should be free to all and everyone should be left alone to make their own decisions. "That's the path of morality." Her ethical views are hard to pinpoint. She proposes that vaccines be priced at zero but the decision whether to "buy" be reserved solely to individual discretion.
Rabbi David Wolpe of Sinai Temple in Los Angeles says vaccination is a religious obligation and that refusing protection for a serious disease is a sin. However, his religious argument is predominantly utilitarian:
I am aware of the objections to vaccinations. Certain vaccines may prove ineffective or even dangerous.There is a risk attendant to any medical procedure, any drug or intervention. But as a class over the years vaccines have wiped out diseases that were scourges of humanity.
Wolpe judges others' ethics on the basis of his own values and the choices he makes on behalf of his "family" (which presumably means his children):
There may be questions on the margin. Specific vaccinations can be doubted, or specific ailments borne. The principle endures. I have gotten a flu shot each year and will get the swine flu shot this year. So will my family.
Normally, religious obligations are thought to apply universally, or at least universally within one's religious community. Wolpe does not say, for example, whether this religious obligation applies to Jews who are allergic to eggs. Many vaccines, including those targeted at influenza, are manufactured using egg cultures and can provoke a wide range of adverse reactions, including death by anaphylactic shock.) Presumably it is not a sin to decline vaccination if there is reason to believe that doing so would be deadly. But not all egg allergies are this severe. Would Wolpe excuse those with "serious" egg allergies? How "serious" would they have to be? This question has a utilitarian answer, but it doesn't if a genuine religious obligation is involved.
James Standish of the Seventh-day Adventist Church also approaches the question with greater regard for individual autonomy, but in some cases he would allow the State to overrule parents who prefer that their children not be vaccinated:
In the case of diseases that result in high rates of death or permanent disability, society has a moral obligation to act to protect the child, even if by so doing the religious beliefs of the parents are violated. But this cannot be done lightly and the intervention must be done in as limited a manner as possible to achieve disease prevention. In the case of some vaccines, however, the balance must go to the parent's beliefs. For example, although tens of thousands of American die from the seasonal flu every year, there is no general mandate that everyone receive the seasonal flu vaccine. Why would society force religious objectors to take a vaccine many Americans fail to take for a variety of other reasons?
Thus, Standish says the consequences risk of H1N1 influenza is not great enough to justify State intervention but he clearly implies that a principle is lurking out there:
A careful balancing of circumstances and rights does not provide easy answers, but simplistic answers are seldom the best answers to complex questions.
United Church of Christ pastor Susan K. Smith offers a public health-based interpretation of Old Testament laws:
It was the Israelites, according to the Hebrew scriptures, who first instituted quarantines to halt the spread of what they thought might be a communicable disease. A person inflicted with certain maladies, especially leprosy, was to stay "outside the camp" until he or she was healed. Lepers were actually put into separate villages and were not allowed to re-enter society until they had been declared healed by the priests.
I call that the ancient form of a vaccine, an attempt to save society.
Smith says she has instituted public health measures at her church, and is willing to follow Old Testament principles up to a point:
I am teaching my congregation rules of hygiene so as to help thwart the spread of the disease and am encouraging those of my members who feel sick to stay home. We provide antiseptic hand cleanser and encourage people to use it after shaking hands and before they leave the church.
Were a large number of the congregation to get sick with the flu, we would institute a quarantine.
Smith sides with public health, but in a way that is more consistent with paternal libertarianism than the exercise of clerical authority. No one is compelled to use hand sanitizer, and members of her church who are sick are probably advised to stay home instead of attending services. Her position seems to be precautionary utilitarianism:
There is a time, I think, when individual rights have to take a back seat to the well being of the institution or society. If getting an H1N1 vaccine will help keep more people well, then I think we who should ought to get it. Saving masses of people from illness or possibly death by getting a shot is not an infringement on my rights. It is a moral and ethical obligation.
Susan Brooks Thistlethwaite, who is a senior fellow at the liberal Center for American Progress and former president of the UCC-affiliated and theologically liberal Chicago Theological Seminary, attributes public distrust of the H1N1 vaccine to political conservatism:
[I]n the last few decades, religious and political conservatives have mounted an all-out assault on the validity of science. From denying evolution to denying the increasing evidence for climate change, conservatives have undermined the trust of many Americans in scientific method. Any scientific method.
Thistlethwaite does not respond to the questions posed by the Post, and provides no ethical or moral arguments to examine. She also appears to be unaware that prominent vaccine opponents, such as Robert F. Kennedy, Jr., David Kirby, and the aforementioned Bill Maher, reside on the political Left.
Two panel members offer perspectives that are unresponsive to the Post's questions but nevertheless very interesting.
Anglican Bishop Nicholas T. Wright admits that he does not know anything about vaccines, and consequently he declines to opine on ethical or moral questions that might be raised. (That none of the other panel members are virologists has not deterred them from opining.)
Wright addresses a related but different question that is within his field of expertise: the use of the common cup to serve Communion. He says this was recently banned by the Church of England (which this Q&A appears to confirm) in response to "a great panic."
I suspect all that this means is that England has become a society of neurotics, where every slight problem that arises brings new rules and regulations, driven not so much by real safety fears as by the desire not to be sued if something goes wrong... not that anyone in the U.S. thinks like that, do they?
Then there is Talmudic scholar Adin Steinsaltz, who rejected the premise of the Post's questions:
The ethical question concerns two groups of people: journalists and medical entrepreneurs. The news media were very active in promoting the swine flu. It got lots of publicity, not all of it accurate, nor measured. At the same time, the medical entrepreneurs found a new source of profit.
If we knew for a fact that the vaccine is completely safe and sure, then it would be just a matter of calculating the costs vs. the danger. As it is now, the malady itself is imprecisely defined, and the help that the vaccine provides is also not very clear. So there are indeed two ethical questions: How much one may ask the journalists to be precise, even when it means a loss of big headlines? And how should medical companies weigh profit vs. value. If these questions have to be raised, sometimes it has to do with human swine rather than the poor four-legged ones.
