When President Joe Biden announced last month that the U.S. would offer a third vaccine dose to Americans who had already received two doses of the Pfizer or Moderna vaccines, he exposed a divide between an administration that has pledged to “follow the science” and many prominent health experts who disagreed with the decision. I am a physician and public-health professional specializing in infectious diseases, and I can think of many potential scientific, regulatory, logistical, and ethical objections to Biden’s announcement.
But this was not, fundamentally, a question for science. It was a question for democracy.
Given that elected officials’ primary obligation is to protect the safety of their constituents, Biden made a rational judgment when presented with evidence that a third dose might provide additional COVID-19 protection to vaccinated Americans and that the United States has sufficient capacity to supply and deliver that third dose.
On social media and in interviews with reporters, though, many experts argued that the administration should wait for more data showing that vaccine effectiveness has declined, focus on providing vaccine access overseas rather than incrementally more immunity to Americans, or both. (At an FDA expert panel’s hearing on Friday, one important scientific issue—limited data about safety of a third dose in young adults—likely led many members to restrict the third dose to persons older than 65 or at high risk.) But when politicians and scientific experts come to different conclusions about how to protect public health, no one should categorically assume that the latter are right and the former are wrong. They have very different obligations.
The COVID-19 pandemic has created a new public-health commentariat, particularly on Twitter and other social-media sites, an important source of COVID-19-related news for about 40 percent of Americans. Many experts quoted in prominent publications and on television are university-based physicians, epidemiologists, or virologists with sterling credentials on matters of science and medical care.
Some of these health experts have been quick to criticize individuals who offer opinions about COVID-19 matters despite having no health-related training or experience. (For many scientists in my Twitter feed, the statistician and political forecaster Nate Silver’s comments are a consistent source of ire.) The term epistemic trespassing, originally coined by the philosopher Nathan Ballantyne, has gained currency among physicians and scientists who believe that economists, data scientists, engineers, and other public commentators should show humility and self-awareness when making recommendations outside their domain-specific knowledge.
Yet many physicians and scientists appear unaware of their own epistemic trespassing. Medicine, epidemiology, and virology are scientific disciplines fundamental to the control and prevention of infectious disease. Using the methods of epidemiology, for example, we can try to calculate how severe a burden a disease imposes and how well any proposed intervention will ease that burden or prevent the disease altogether. The practice of public health involves using that information to improve the health of people within a specific jurisdiction, accounting for the legal, economic, and political conditions that apply there. Public-health practitioners cannot just “follow the science.” They must account for many other factors, including the legality, cost, feasibility, and social acceptability of any disease-control initiative. In the United States, public-health practice must account for laws and cultural norms that limit the power of government and strongly favor protection of individual rights over collective rights.
In any democratic jurisdiction, legal and economic factors, along with the opinion of powerful interest groups and the general public, may trump scientific evidence—particularly when that evidence is uncertain and incomplete. And although health experts almost uniformly believe that preventing illness and death should be the highest priority, eliminating risk altogether carries a cost, and humans differ in how much risk they are willing to tolerate and how much they want to be inconvenienced to reduce that risk. It’s one reason that researchers have found a correlation between effective early response to the COVID-19 pandemic in countries with tight adherence to common social norms—a category that includes Vietnam and Singapore but not Brazil or the United States.
To an epidemiologist, a physician, or a virologist, this process of making public-health policy tends to look chaotic, and many outcomes seem not entirely rational. In 2013, Chris Tyler, a science adviser to the British Parliament, memorably offered 20 recommendations to scientists about policy making. Several items on his list are particularly relevant to the COVID-19 pandemic: “There is more to policy than scientific evidence,” “Starting policies from scratch is rarely an option,” and “Policy and science operate on different timescales.” On this last point, Tyler elaborated: “When policy makers say that they need information soon, they mean within days or weeks, not months. This is not a flaw of the system; it is the way it is.”
On many issues, fortunately, no gap exists between “following the science” and the everyday practice of public health. Requiring measles vaccination for school entry and restricting smoking in indoor public spaces are evidence-based policies that protect human health with no significant downside. COVID-19, however, has caused many “wicked problems”—a phrase coined in 1973 for policy issues that are difficult to solve because the relevant evidence is incomplete or contradictory, because a large number of people or opinions are involved, because any solution would impose a large economic burden, or because any response touches upon a host of other problems.
For instance, during the surge in Delta-variant infections, should a community mandate indoor masks, vaccines, both, or neither? The scientific evidence clearly indicates that a person who wears a mask or completes the vaccination series, or both, is at reduced risk of acquiring and transmitting COVID-19. But if businesses are now required to implement either a mask mandate or a vaccine mandate, does the government have enough people to inspect compliance and process violations? Does the government have the legal authority to impose those mandates? When businesses inevitably sue, will courts more readily accept the arguments for mask mandates than for vaccine mandates, or vice versa? How does the public want to balance the rights and privileges of the vaccinated and the unvaccinated? The complexity of these issues initially led the country’s two largest localities to respond to the summer surge of Delta infection with two different approaches to commercial establishments, such as gyms, restaurants, bars, and indoor entertainment venues: a mask mandate in Los Angeles County and a vaccine mandate in New York City. (Last week, L.A. County announced a limited vaccine mandate for some commercial establishments too.)
The most wicked of all the wicked COVID-19 problems has been when and how to resume in-person school. How much COVID-19 risk is too much risk? Whose harms matter more—those of employees, children, parents, or vulnerable people in the community? Which harms matter more—COVID-19 infections or the social, emotional, and educational losses that children have suffered during the pandemic? Fundamentally, these are judgment calls for elected officials, not questions of science. (Full disclosure: I advise New York City as a consultant on pandemic policies, including those involving schools.)
While “following the science” is more complicated than it sounds, experts should expect politicians to at least start with the science. That is, these leaders should forthrightly acknowledge the realities of any public-health crisis rather than deny facts, cherry-pick data, and downplay problems for ideological reasons. And elected officials should not claim to be making purely scientific decisions when reaching complex policy judgments—about whether Americans should be offered booster shots, for example—based on multiple factors.
Likewise, journalists amplifying the voices of the public-health commentariat should give sufficient weight to discussions about the nonscience issues that determine COVID-19 policy. News outlets should press health experts and others to explicitly discuss the trade-offs inherent in any recommendation—and to explain how their own values inform their views. While serving as the chief health adviser to the New York City mayor, I always started complex internal policy discussions by saying, If the most important policy priority is to reduce COVID-19 illness and death as much as possible, then the scientific evidence indicates that the city should do X. Although “follow the science” has a comforting ring, a more accurate guiding principle would be: Start with the science, and let democracy decide.