When doctors meet a patient for a new complaint, we make a list of different possible explanations for the problem—a differential diagnosis—and try to determine the correct diagnosis, while starting treatment for the most likely one. After this initial assessment, as test and imaging results come in, we may alter the differential diagnosis and treatments.
Public-health officials dealing with a new pathogen, like the coronavirus that causes Covid-19, go through a similar process. They must recommend policies with incomplete information and adjust them over time. But unlike physicians, they do so in public, and sometimes under intense scrutiny.
Dr. Anthony Fauci—and this is not meant as criticism—has epitomized the public-health diagnostic process with multiple, incorrect, early pronouncements: In January and February, he downplayed the risk of person-to-person spread; he expressed doubt that asymptomatic people could transmit the virus; in late February, he reassured the public that, “at this moment, there is no need to change anything that you’re doing on a day-by-day basis”; and in March, like many other public-health officials here and abroad, he said that, outside of health-care personnel, ordinary people should not wear masks. In fact, both Fauci and Surgeon General Jerome Adams suggested that mask-wearing could increase a person’s risk of being infected. All these assertions proved wrong.
We know a lot more about the virus—how it’s transmitted and how to treat it—than we did a few months ago. For instance, the coronavirus can spread person-to-person from both symptomatic and asymptomatic people. Dr. Fauci now espouses the opposite of each of his earlier statements, but there is nothing wrong with that. As economist John Maynard Keynes purportedly said, “When the facts change, I change my mind—what do you do, sir?”
The lesson: in evolving public-health emergencies—despite the demand from some politicians to “Listen to the science!”—science alone can’t always determine the best course of action. Policymakers have to balance multiple, competing factors while working with imperfect information and uncertain science. In a pandemic, infectious-disease experts can advise that shutting down the economy will limit the spread of deadly disease. But experts from other fields might warn that the same action will also throw millions out of work and lead to increased deaths of people unable or unwilling to obtain medical care for emergencies and chronic diseases, more suicides, and more drug and alcohol abuse.
Shifting advice from public-health officials can also undermine their public credibility and erode public confidence. It becomes easy to ignore warnings to “follow the science” when the science is fluid. This is particularly true when it becomes clear that the original justification for the advice was misleading. Americans were told that there was no evidence that face masks were protective, or that, at best, they might help protect other people, but not the mask-wearer himself. Now Fauci has explained that the main rationale for discouraging mask use was not really the belief that they don’t work but to preserve an adequate supply of masks for health-care workers. Small wonder that some opponents of mandatory mask-wearing say that they’re not convinced masks are helpful, and that they may even be harmful. They can be forgiven for wondering why masks were necessary and protective for health-care workers but not for them.
In discouraging mask use, Fauci—for decades, the nation’s foremost expert on viral infectious diseases—was not acting as a neutral interpreter of settled science but as a policymaker, concerned with maximizing the utility of the limited supply of a critical item. An economist could have told him that there was no need to misinform the public. Letting market mechanisms work and relaxing counterproductive regulations would ease shortages. Masks for health-care workers would be available if we were willing to pay higher prices; those higher prices, in turn, would elicit more mask production.
As the Covid-19 crisis developed, the FDA removed regulatory barriers to using existing supplies of respirators and masks. On March 2, the FDA approved health-care use of N95 respirators approved for industrial use by the National Institute for Occupational Safety and Health (NIOSH). These respirators, which account for the majority of respirators produced, had not been regulated by the FDA but meet identical filtration standards to FDA-approved respirators. In April, the FDA increased mask supply by granting an emergency-use authorization waiving previous agency approval requirements for masks.
As we learn more about the science of Covid-19, and market responses kick in, our policy choices will ideally become easier. Open, honest public communication will be crucial, in any case. Both sides of the political spectrum should acknowledge that the science is not always clear—and even when it is, it rarely mandates a specific policy direction.
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