Can you handle herd immunity? Ask these philosophers
The idea of “herd immunity” through infection, ruled out almost everywhere six months ago, is now under serious consideration in capitals across the world.
The idea of “herd immunity” through infection, ruled out almost everywhere six months ago, is now under serious consideration in capitals across the world. It’s a hugely complicated scientific issue, but it also poses an unavoidable moral dilemma. I hope what follows will help to frame that moral question and make it easier for all of us to participate in a very difficult debate. This is the fourth essay in a series that has been coming out at roughly two-month intervals since the outbreak of the pandemic. To get the newsletter delivered directly to your inbox, sign up here.
Six months ago, populations across the world acquiesced, with minimal debate, to lockdowns to fight the Covid-19 pandemic. Amid confusion and horrifying death tolls, the default position was to protect the elderly and minimize loss of life.
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Now the question is different. In the U.K., which is limiting social gatherings to six people, Boris Johnson’s government faces a rebellion from MPs in his own Conservative Party and from a campaign group called Keep Britain Free that says Johnson has “used lockdown to strip away our liberties.” Anti-lockdown protests have broken out across the U.S., with even New York’s ultra-Orthodox Jewish community burning masks in public. With six months of experience, people know that lockdowns exert a terrible toll. Even after the shocking news of President Donald Trump’s infection, the tide in the U.S. is moving toward reopening, allowing people to get sick and building immunity that way until a vaccine arrives to ease the dilemma. So there is a new question: Is a “herd immunity” strategy acceptable?
Both scientific and moral judgments are needed to form an answer. Reaching herd immunity via infections involves admitting that society will not try to save people from getting sick, and that some avoidable deaths will occur. Science and ethics interact. If scientists can show that herd immunity is within reach, these costs are lower.
But scientists on both sides of the debate made wildly inaccurate predictions earlier in the pandemic, and they remain divided over the potential human cost. Even then the moral question of what cost is acceptable remains.
The level of immunity in the population needed before a virus dies out varies from disease to disease. It is as high as 90% for measles. The scientific journal Nature estimates that the threshold for Covid-19 might be 50% of the population. The bad news: For countries such as France and the U.S., “this would translate into 100,000-450,000 and 500,000-2,100,000 deaths, respectively.”
Meanwhile, there are influential epidemiologists who believe that the herd-immunity threshold has been reached in regions that have already suffered major outbreaks. They argue that Covid-19 can be choked off when as little as 20% of the population has been infected.
What do they propose? This week, epidemiologists from Oxford, Harvard and Stanford launched the so-called Great Barrington Declaration, which recommends moving to a strategy called focused protection. They also briefed officials in the Trump administration. This is how Sunetra Gupta, the Oxford professor who co-authored and signed the declaration, defined the idea earlier this year:
Herd immunity is just a technical term for the proportion of the population that needs to be immune in order to prevent the disease from spreading. … It’s a fundamental epidemiological concept, which clearly has been subverted. The truth is that herd immunity is a way of preventing vulnerable people from dying. It is achieved at the expense of some people dying, and we can stop that by protecting the vulnerable class in the process. In an ideal situation, you would protect the vulnerable as best you can, let people go about their business, allow herd immunity to build up, make sure the economy doesn’t crash, make sure the arts are preserved, and make sure qualities of kindness and tolerance remain in place.
Centuries of moral philosophy have left us with different tests for decisions like these. Gupta’s version of “focused protection” passes some, but not others.
The greatest good of the greatest number
Utilitarianism, promulgated by Victorian liberal reformers in 19th-century England and influential ever since, does not look at people’s duties or rights, but rather judges actions by their consequences. In its crudest form, if an action benefits “the greatest good of the greatest number,” then the utilitarian calculus will justify it. Thus, sacrificing a few can be justified, providing this clearly benefits the many.
When dealing with rationing health care, utilitarian choices involve concepts like the QALY: the quality-adjusted life year. How many years of life will be lost when comparing two alternative paths, and how good will those extra years of life be? A healthy teenager takes priority over a pain-racked and disabled 85-year-old; the QALY measurement aims for a quantitative solution to harder choices, such as between a fit 40-year-old and a disabled 20-year-old.
Now we know the costs of lockdowns, and they are high. Listing those costs arouses great passion. Beyond the demonstrable economic damage, there is harm to mental and physical health. The conditions of the last six months have forced upon us an unnatural way for humans to live — and the current strategy requires a commitment to live this way until enough people have access to a safe and effective vaccine.
On a utilitarian basis, then, a herd-immunity strategy has much to commend it. A comment in response to a column by Bloomberg Opinion’s Tyler Cowen questioning how close society is to approaching herd immunity says it all: “If you could add one year to the life of everyone over 65 by destroying the futures of 25% of the people under 20, would that be worth it?” If that is the choice, most of us, including all utilitarians, would say “No.”
But the choice is not as clear as it seems. “It’s not just a trade-off by letting Grandma die,” says Arthur Caplan, head of bioethics for the NYU Langone medical system. “You are still going to have to pay hospital costs to try to save Grandma before she dies. That’s an additional burden for hospital systems. And then some percentage of people will be disabled for many years. How many, we don’t know. When the herd-immunity people point to the mortality statistics, they aren’t being honest.”
The long-term harms of Covid-19 are not yet known, so the costs of herd immunity are also unknown. Some dismiss reports of “long-haul Covid” as overwrought and point to the long-term effects that can result from flu. But the questions do cast doubt on the utilitarian calculus.
Liberty and survival of the fittest
Opposition to lockdowns has been led by libertarians, who give priority to the human right to self-determination. Libertarianism’s distinguished history goes back to the British philosopher John Locke and the Founding Fathers of the U.S. In its modern incarnation, libertarianism is associated with the 19th-century British thinker Herbert Spencer and, most recently, the Russian émigré novelist Ayn Rand. Libertarians don’t endorse irresponsible behavior, but they do believe such decisions as going to the office or wearing a mask should be left to responsible, informed individuals.
This naturally rules out strict lockdowns. But if we are no longer to lock down, are we prepared to take libertarianism to its logical conclusion? Jeremy Corbyn, former leader of Britain’s Labour Party, summed up the argument against this line of thinking, complaining that he had not discussed herd immunity since he worked on a pig farm 40 years ago. “It was absurd: that you’d build up herd immunity by allowing people to die,” he said.
Social Darwinism, or leaving people to the cruel judgments of nature, originated with Spencer, who coined the term “survival of the fittest” several years before Charles Darwin published “On the Origin of Species.” In “Social Statics,” Spencer argued for “weeding out those of lowest development.”
Republican Senator Rand Paul of Kentucky, one of the best-known libertarians in American life and a vocal opponent of lockdowns, used similarly Darwinist logic when he asked in the Senate whether “man is really capable of altering the course of an infectious disease through crowd control.”
Eschewing “crowd control” entails allowing the weak in society to perish. This is true not only of the elderly, but also those hit hardest by Covid for a range of reasons — most notably, the poor and minorities. Will people follow libertarian logic this far?
The golden rule
Doctors take their ethics from the Enlightenment philosopher Immanuel Kant, who based morality on the biblical “golden rule” — that we should not do to others what we would not want done to ourselves. This aligns with Christian teaching, and underlies medicine’s Hippocratic Oath to “first do no harm.” It also undergirds the influential theory of the Harvard political theorist John Rawls that we should make choices as though behind a “veil of ignorance,” not knowing if we are the worst off in society.
As a result, some utilitarian trade-offs can become impossible to justify: “I think the arguments are pretty much stacked up against herd immunity,” says Caplan of NYU Langone. “First, it violates the ‘do no harm’ principle of medicine. Many doctors would not be able to do it. They just could not stand by.”
Even with improved care, Caplan points out, the mortality rate for those over 70 catching the disease is as high as 7%. “Sadly, you are going to have to write off Grandma to run the experiment. I think Grandma would have to stay away forever,” Caplan says. “If it’s around 50 or 60 percent to get herd immunity, I’m not sure you could get protection for the highly vulnerable ever.”
Caplan also objects that “we don’t know how long immunity lasts.” If it only lasts a matter of months, then we have no choice but to wait for annual vaccinations, similar to the flu.
Abandoning the vulnerable to their fate is unconscionable. But would locking them down until herd immunity is reached pass the golden rule?
Perhaps not. With people not distancing or wearing masks, entering the outside world would be even more perilous, and the vulnerable would be even more isolated. This risks creating a group of second-class citizens.
In a column for a Danish newspaper, a disabled Swedish writer said this about life in his home country, the developed nation that has made the clearest attempt to reach herd immunity without lockdowns:
Soon enough, it was clear that the world had an intersectional approach that Sweden lacked. They understood that people of color, poor people, old people and disabled people were bearing the brunt of the virus, and dying. We couldn’t isolate and protect ourselves in the same way. The right thing to do, once we’d attained an uncontrolled community spread, was obvious. Put the whole population into quarantine until you’re in control of the spread, and use the time to establish a comprehensive testing plan. That would’ve given everyone a short spell at home — rather than Sweden’s incessant and lethal isolation for “at-risk groups” only.
Even with protections for the vulnerable, a herd-immunity strategy might still discriminate against certain populations. It’s hard to reconcile that with the golden rule.
The common good
What of looking for “the common good” in society, an idea that’s often labeled “communitarianism”? These ideas go back at least as far as the French thinker Jean-Jacques Rousseau and his social contract, and they appeal to socialists and to cultural conservatives alike.
The echoes of social Darwinism make the idea of herd immunity anathema for communitarians. Ben Bramble, a philosopher at the Australian National University and author of “Pandemic Ethics: 8 Big Questions of COVID-19,” argues that lockdowns benefit society: “Choosing to sacrifice many old and vulnerable citizens, and greatly burden the socio-economically disadvantaged, mainly in order to spare the young and healthy (and the wealthy) some economic pain, is liable to poison relations between these groups. How could our relationships with them recover? This could irreparably damage the fabric of our society.”
By contrast, he writes, if the young and healthy take a hit to protect these groups, it could bring everyone closer, enhancing our lives and “helping society function better.” As for the pain of those locked down, he says, government support can alleviate it.
But this argument may not be as clear as it looks. Gupta, the Oxford epidemiologist, says people should think of trade-offs at a “communitarian” level, and suggests that the young and healthy can do their bit for society by becoming infected.
Noting that young people are terrified of infecting a friend or grandparent, she complains that the “chain of guilt” is “somehow located to the individual rather than being distributed and shared.” She adds: “We have to share the guilt. We have to share the responsibility. And we have to take on board certain risks ourselves in order to fulfill our obligations and to uphold the social contract.” Young people who hasten herd immunity are to be thanked for ensuring that “the social contract is being properly transacted.”
Bramble disagrees. “It is unbelievable to me that she thinks young people have a moral duty to get infected in order to get us closer toward herd immunity.”
Leave it to the scientists
Six months ago, I wrote that “we are all Rawlsians now” — that faced with the pandemic, governments and societies had reacted as though they had a duty to put themselves through great privations to protect the sick and elderly. Now we know that this was something of an illusion. Many died lonely and unnecessary deaths in nursing homes, economies faltered, and rowdy libertarian opposition to lockdowns soon began.
Trump’s illness highlights that the disease is still with us, while his swift recovery so far shows that our ability to treat it and keep victims alive is improving. With new information, then, the same choices need to be made again. But now the balance has shifted away from strict lockdowns, and the utilitarian position has become the default. After the spring’s historic economic seizure, the clarity of the golden rule has given way to a complex trade-off.
How complex? As Scandinavia battled to come to terms with Sweden’s epidemiological experiment, Finnish philosopher Matti Hayry laid out the problem. “We simply do not know which choice will, in the end, be the best life saver, health promoter, or quality-adjusted life year producer overall,” he wrote. Since many of the ill effects of the two choices are not commensurable, he argued, utilitarian decisions cannot be made, “let alone communicated accurately to the general public.”
If the public is not going to try to save the most lives, he added, then “the most severe obstacle for utilitarian truth telling” will be that the choice is unpalatable. If the government tries to prioritize reviving the economy, then “telling the truth would also require them to predict how many lives would be lost as a consequence.”
He predicted that “people would then argue that the sacrifice is immoral and point out that the lives lost would be in vulnerable groups.” Or they may not.
We don’t know. What we do know is that the ball is back in the scientists’ court — philosophers can only help us come to a decision that requires good data. It’s up to science to illuminate the costs, and to leaders to communicate those costs to the population. The difficulty of comparing two ugly alternatives may reveal the great limit of utilitarianism: that it sometimes requires comparing things that cannot be compared.
(This story has been published from a wire agency feed without modifications to the text.)