Science in Review — January 2013

After a holiday hiatus, I am resuming my “director’s cut” look at one of my weekly Facebook posts. Look for this feature on the last Wednesday of the month.

Not if I were the last man on Earth to be unvaccinated.

“Not if I were the last man on Earth to be unvaccinated.”

The most discussed topic of the past month was mandatory flu vaccines for healthcare workers. In the midst of a more-severe-than-usual flu season, there have been several stories about nurses losing their jobs for declining the vaccine. We discussed an incident in Indiana reported here and here, and a case from Missouri covered here. In both instances, the nurses cited religious beliefs as contributing to their refusal, with some mention of safety concerns. They felt that they had a right to decide what went into their bodies, and that mandatory vaccination policies conflicted with that right and their religious freedoms.

The Facebook discussion was fairly positive in favor of vaccination. There was a consensus that vaccinating healthcare workers was an important measure for protecting patients and minimizing the spread of disease in healthcare settings, although some folks did stop short of endorsing blanket mandates. One participant noted that these policies are sometimes applied across all hospital departments regardless of the amount of contact with patients; many transcriptionists, chart coders and other administrative personnel work offsite.

Ultimately, the topic of herd immunity was taken up. Herd immunity is the phenomenon where, once enough individuals in a population are vaccinated or immune to an infection, then the population as a whole is immune in a certain sense. At that point, even individuals who never got vaccinated experience some protection. This paper on herd immunity and influenza was cited; it concludes that an 80-90% level of vaccination would be required to achieve herd immunity in most years (both the virus and the vaccine can vary from year to year). This level is far higher than the 50-60% coverage typically achieved in the US.

The talk of herd immunity got me thinking again about the tension over vaccination expressed by the nurses. At the population level, research and public health experience has shown that the benefits to administering vaccines almost always outweigh the risks. But as more and more people receive the vaccine, that risk/benefit calculation for each individual begins to shift. At some point, the risk of side effects to an individual becomes greater than the chance of getting exposed to the disease. As an extreme example, no one is lining up for the smallpox vaccine, even though the virus still exists and thus there is some infinitesimal but nonzero probability of contracting smallpox. And even when the disease is not that rare, one might still be inclined to hope that enough other people will get the vaccine to provide herd immunity in order to avoid even the minimal risk of side effects.

Thus, and I say this as someone trained at a public health school and who makes sure his kids get all the recommended vaccinations, we see that vaccines are not an absolute good. The risks and benefits should be considered in each individual’s context. And if someone has incomplete information or inaccurate information about the risks and benefits, or about the cost of side effects and the cost of getting sick, or about how to accurately reason about the probability of rare events (something science has shown humans to be not very good at, at least innately), then you can start to understand how we can reach different conclusions on a given individual’s need to get a particular vaccination.

And yet we know that if everyone rejects the vaccine, the health outcome for many individuals and for the population will be worse. So, how do we resolve that tension? Presumably education is a component, so everyone is at least starting from the same point when evaluating relative costs. Are vaccination mandates another tool? Is it appropriate to have a policy which says, in essence, that you need to get a vaccine because it is better for us all collectively if you do, even though it involves some risk to you personally? As Christians, should we endorse such policies, since they encourage servanthood and putting the needs of others above our own? Or do such policies undermine the personhood of individuals imbued in them by their Creator?

I also wonder about the appeal to religious freedom. As participants in a secular, pluralistic society, how do we decide whether this is a religious belief meriting protection? We might wish to say that protected religious beliefs must be the teachings of well-known religions. But who decides which ones make the cut? Doesn’t the very notion of deciding represent a restriction on religious freedom? Recall that several states were founded by people whose religious beliefs weren’t accepted by the majority of their society, prompting them to create their own new society where their religion would be tolerated. Isn’t the whole point of the First Amendment to allow people to act their conscience rather than have to adhere to particular pre-approved sets of doctrines? Is there any grounds on which to deny any particular belief, even if it is held by one person?

As I ponder that one, I’m struck with the feeling that we’ve reached a point where “religious beliefs” means “anything one believes strongly without, or in spite of, evidence.” If that’s the case, then it seems hard to deny any particular such belief. Is that where we are? If so, how do we use science to set policy if everyone is entitled to actively ignore some amount of evidence?

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Andy Walsh

Andy has worn many hats in his life. He knows this is a dreadfully clichéd notion, but since it is also literally true he uses it anyway. Among his current metaphorical hats: husband of one wife, father of two elementary school students, reader of science fiction and science fact, enthusiast of contemporary symphonic music, and chief science officer. Previous metaphorical hats include: comp bio postdoc, molecular biology grad student, InterVarsity chapter president (that one came with a literal hat), music store clerk, house painter, and mosquito trapper. Among his more unique literal hats: British bobby, captain's hats (of varying levels of authenticity) of several specific vessels, a deerstalker from 221B Baker St, and a railroad engineer's cap. His monthly Science in Review is drawn from his weekly Science Corner posts -- Wednesdays, 8am (Eastern) on the Emerging Scholars Network Blog. His book Faith across the Multiverse is available from Hendrickson.

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    John Boyland commented on January 30, 2013 Reply

    Perhaps part of the problem is that we suppose there is a fixed idea of “religion” out there. American law depends on the existence of such a definition. But this is a chimera. As Christians, we appreciate that the secular state doesn’t penalize us for our views, at least not very often, and not yet. But there can be no long-term confidence that this situation is stable. At some point, a society based on atheism will be unable to tolerate public expressions of orthodox Christianity.

    So should a Christian society permit people who refuse vaccination to be employed as public health workers? We can try to answer such questions without talking about freedom of religion.

      Andy Walsh commented on January 31, 2013 Reply

      Yes, exactly; when the First Amendment was written, it seems there was a (perhaps unspoken) consensus on what constituted a religion, and so there was no need to define it. However, since we have moved away from a consensus on that topic, protection of religious freedom has the potential to become quite broad. So, how do we create a definition?

      Also, I agree that much can be said about vaccination and healthcare workers without invoking religious freedom. And personally, my gut reaction is that it isn’t a religious freedom issue. But the point is that in each story, the nurses in question cited religious beliefs as a justification for refusal, and invoked religious freedom to question the legitimacy of their firings. And so the question is whether those are valid claims, either from a Biblical perspective, or from a secular, legal perspective.

    theurbanresident commented on January 30, 2013 Reply

    As a healthcare and public health professional, I would argue that there is a strong case IN FAVOR OF mandatory influenza vaccination for HEALTHCARE PROFESSIONALS:

    1) In protection of healthcare workers: Healthcare workers are much more frequently exposed to both the influenza virus, which during epidemic proportions is concentrated in the hospital/healthcare setting, as well as other respiratory illnesses that can cause co-infections or co-morbidities in the setting of an influenza infection. Because of the high transmissibility of influenza, even non-clinical staff members may be at higher risk from simple proximity to active clinical staff (e.g. in the cafeteria). Strict proof of vaccination or immunity is often required for other infectious organisms, such as varicella (chicken pox), measles, mumps, rubella, etc. Of note, it is impossible to achieve herd immunity within the hospital setting by definition (high prevalence of infected individuals). During the SARS epidemic,

    2) In protection of patients:
    A) Because of the incubation period in which a healthcare worker is able to transmit an infection while being relatively asymptomatic, it is even more critical to vaccinate healthcare workers who come into frequent contact with patients who are, by definition, already suffering from another illness that may constitute a co-morbidity.
    B) The healthcare workforce may be reduced precisely because of worker illness at the exact time that they are needed the most (e.g. overcapacity during an epidemic). Because immunity takes 2-4 weeks at least to fully develop, it is too late to then protect this vulnerable population during an epidemic season. These problems may eventually translate into suboptimal hospital performance due to short-staffing, which then results in compromised patient care.
    C) Infection can easily spread to the population surrounding a hospital through the hospital itself. Patients who were admitted to the hospital for non-influenza related illness are at higher risk of contracting the virus due to increased exposure, and then may bring it home to their communities on discharge. High turnover rates at hospitals, especially during over-capacity times such as during an epidemic, may increase this mechanism of spread.

    3) Legal precedence for immunization:
    Just as food servers are under moral and legal obligation to not serve food while ill, or to wash hands at all times, healthcare professionals by definition are employed in the service of protecting and improving health. Since other healthcare

    However, I would argue that there is a valid case AGAINST mandatory PUBLIC influenza immunization.

    1) Due to the rapidly mutating nature of the influenza virus, true herd immunity may not be a realistic goal, though there will likely still be some benefit to those who have not been vaccinated.

    2) Because the influenza vaccine must be reformulated every year, it is possible that previously unrecognized complications may outweigh the benefits of mandatory vaccination. Consider this disturbing article about the H1N1 (swine flu) vaccine:
    In this case, adjuvant in the vaccine (which was NOT made available in the USA: an alternative vaccine was used). There were approximately 80 flu deaths theoretically prevented, while up to 200 individuals may have had narcolepsy triggered as a consequence of the vaccine.

    3) Compulsory vaccination would be very difficult to enforce, especially in determining punishment and justification for punishment.

    In regards to religious objection to immunization:
    Most research studies on immunization refusal have found that there is varying degrees to which refusal is permitted, based on the specific school/state/federal mandate present. Also, the rate of vaccination compliance is certainly linked to the “strength” of the exemption criteria. If there is a loose exemption criteria, meaning it is easy for someone to object on either religious or philosophical grounds, the rate of vaccination drops sharply enough (below the 90% threshold) to render herd immunity useless, thereby making the mandate essentially useless as well.

    *As an interesting trivia note, Jonathan Edwards, the legendary American theologian, died from a vaccine complication. It should be noted though that he was a strong advocate of the vaccine, which is why he got it, and why he died. I doubt he would have changed his mind anyways.

      Andy Walsh commented on January 31, 2013 Reply

      Thanks for spelling out the public health case for vaccination of healthcare workers. Personally, I find those arguments compelling and I would not object to such a policy if I worked in that kind of environment. In some sense, this post was an attempt to understand why some people aren’t persuaded by that reasoning, since it makes a lot of sense to me.

      The observation that loose exemption criteria make a mandate effectively useless is an interesting one. It seems to me we currently occupy an interesting point in this space. Pragmatically, we know we can’t just exempt anybody for any reason, and so we narrow the criteria for exemption. But it feels like that is largely just pragmatism; as mentioned above, we don’t have a very good definition for religion and so we don’t have very solid philosophical justifications for those narrow criteria.

      On a purely technical note, I am curious why you say that herd immunity is impossible in the hospital based on prevalence. The usual formula for herd immunity doesn’t depend on infection prevalence, at least not directly (one could argue it does impact the effective reproductive rate, which does factor into the herd immunity threshold). So I don’t quite understand why the higher prevalence would make it impossible. If anything, I’d think the biggest challenge to achieving herd immunity in a hospital setting is the constant turnover in population, potentially bringing in new susceptible individuals every day.

        theurbanresident commented on February 1, 2013 Reply

        Hi Andy, thanks for your points. I think you are right in saying that the formula does not technically depend on infection prevalence, but only because the model assumes that those vaccinated are mainly immune/protected from the disease, and I think that that the number of those initially infected must be statistically insignificant/negligibly small in comparison to the total population considered (in other words you must start with a disease-naive population; note that most hospitals are less than 1,000 patients), though I do not know for sure. There are other assumptions: a “well-mixed” population where the distribution and interaction of individuals is relatively random (which is not the case in the hospital, as patients are often cohorted by disease severity and type), and that vaccinated individuals are generally considered to be protected from the disease (the vaccine gives only ~50-60% immunity, and only covers a handful of strains; all strains of influenza mutate very rapidly).

        If the model were to be valid, it would be extremely difficult to achieve herd immunity for the other reasons that we both mentioned. Hope this makes sense. Good discussion!

        Andy Walsh commented on February 2, 2013 Reply

        So, the crux of herd immunity is getting the effective reproductive rate of the pathogen in question to be less than 1, meaning that each infected person, on average, infects fewer than one other person. If that rate is achieved and maintained, then you can see where people will stop being infected.

        When a vaccine is available, that is the most straightforward way to control the reproductive rate. If you vaccinate enough people, essentially you are creating a situation where most of the people an infected person comes in contact with are immune, making it harder for them to pass on the infection.

        Calculating how many people to vaccinate does assume a well-mixed population, so that the probability of coming in contact with an infected person is directly proportional to the number of infected people. I discussed this briefly on Facebook; I’m not sure a hospital fits that model because many hospital employees are required to come in contact with infected people as part of their jobs. Your point about patient cohorts is also apt in that regard. That said, it might be possible to create another model for the probability of coming in contact with an infected person, and calculate the number of people to vaccinate for herd immunity from that model.

        The standard calculations do take into account the efficacy of the vaccine. The 80-90% vaccination coverage recommended by the paper I cited was based on typical values for the efficacy of the flu vaccine. Of course, some years the vaccine is less effective than that.

        I suspect when you talk about needing a disease naive population, you are thinking about the initial reproductive rate, often called R0, of a pathogen. That is the number of people who will get infected from a single infected individual in an otherwise naive population. R0 is part of the calculation for herd immunity, but achieve herd immunity itself does not require a naive population.

    Bo commented on February 2, 2013 Reply

    I think we must all realize that there can be no absolute “religious freedom” just like there can be no absolute freedom of any kind. One person’s freedom must be considered with the freedoms of others and the over all impact of our society. (For example: hate speech, human sacrifice, polygamy, etc.) More importantly from a Christian perspective, any claimed freedom must be aligned with the Biblical teaching. Yes, in making an interpretation/judgement, we are limiting our “freedom” in a sense. However, our faith simply does not allow baseless “freedom.” Much of our obsession with personal freedom is simply the result of our individualisitic culture rather than any reasonable belief. We are a culture who is obsessed with MY right. The great “l/ME” comes before anything else. You can take a look at most controversial debates out there today. Most can be easily viewed from the perspective of “me” vs “we.” (e.g. gun rights, tax policy, immigration, etc.) Perhaps, this is simply a reflection of our fallen state, the darkness in all of us. For Christians, one of the central paradox is that our individuality does not come from ourselves. It is when we “surrender” ourselves completely, lay down our lives on the cross with Jesus for the world, we truly become the real SELF that God meant us to be.

      Andy Walsh commented on February 2, 2013 Reply

      Thanks for summarizing some of the tensions between an understanding of freedom in Christ and the common civic understanding of freedoms and rights. I think it can be hard to recognize that there even is a tension because we proceed along the following train of thought:
      1) The founding fathers were all Christians. 2) The Bill of Rights (and the Declaration of Independence, the Constitution, etc.) was crafted primarily/solely from their Christian perspective. 3) Therefore, all values and virtues espoused by the Bill of Rights are Christian/Biblical.

      But as you point out, that leads to some contradictions, which suggests we might need to rethink that line of reasoning.

      So you make an interesting Christian case for limits on what constitutes an expression of freedom of religion. I wonder though how one might make such an argument from a secular perspective. Is our only recourse in that case the pragmatic empiricism of whatever allows society to get things done?

        Bo commented on February 2, 2013 Reply

        Very good question. What can we do? I believe that these are actually two separate questions. One is what we should do as Christians. The other is what we should do as a society. To answer the first question, we can study the Bible, Jesus’s teaching and theology in general in order to arrive at an reasonable conclusion based on our moral and spiritual understanding. To answer the second question, however, we can not rely on the argument based on our moral and spiritual understanding alone. Obviously, our action and intentions can and should be guided by our principles. But we must realize that in a secular, multicultural, multispiritual world, one simply can not argue successfully based one set of principles. We do not all stand on the same “moral ground.” Sadly, but truly, the only way forward is to be pragmatic, acting on my believes, aiming to achieve the greatest good possible. The goal can not be winning any absolute moral argument. It is clearly that it is impossible to establish a perfect Christian nation/community. We must keep in mind that the goal is not to achieve moral victories. The goal is to exhibit God’s love, to imitate Jesus sacrifice, in order to ultimately save more souls and to be made perfect in His eyes. As relating to the vaccination question, the question facing Christians instead should be what the most loving thing we can do for others. Should we get vaccinated to reduce the potential disease burden of others even if we have reservations? On the other hand, should we force others to get vaccinated against their own belief? What’s the trade off? What’s the most loving choice?

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