Viruses inevitably spread, and authorities have oversold face coverings as a preventive measure.

bus mask mandate
© Charles Krupa/Associated PressA man wearing a protective mask rushes to catch his bus in Boston, June 24.
A hallmark of Covid-19 pandemic policy has been the failure of political leaders and health officials to anticipate the unintended consequences of their actions. This tendency has haunted many decisions, from lockdowns that triggered enormous unemployment and increased alcohol and drug abuse, to school closures that are widening educational disparities between rich and poor families. Mask mandates may also have unintended consequences that outweigh the benefits.

First, consider how the debate has evolved and the underlying scientific evidence. Several randomized trials of community or household masking have been completed. Most have shown that wearing a mask has little or no effect on respiratory virus transmission, according to a review published earlier this year in Emerging Infectious Diseases, the Centers for Disease Control and Prevention's journal. In March, when Anthony Fauci said, "wearing a mask might make people feel a little bit better" but "it's not providing the perfect protection that people think it is," his statement reflected scientific consensus, and was consistent with the World Health Organization's guidance.

Almost overnight, the recommendations flipped. The reason? The risk of asymptomatic transmission. Health officials said mask mandates were now not only reasonable but critical. This is a weak rationale, given that presymptomatic spread of respiratory viruses isn't a novel phenomenon in public health. Asymptomatic cases of influenza occur in up to a third of patients, according to a 2016 report in Emerging Infectious Diseases, and even more patients had mild cases that are never diagnosed. Asymptomatic or mild cases appear to contribute more to Covid-19 transmission, but this happens in flu cases, too, though no one has called for mask mandates during flu season.

The public assumes that research performed since the beginning of the pandemic supports mask mandates. Policy makers and the media point to low-quality evidence, such as a study of Covid-19 positive hairstylists in Missouri or a Georgia summer camp with an outbreak. These anecdotes, while valuable, tell us nothing about the experience of other hairdressers or other summer camps that adopted similar or different masking practices. Also low-quality evidence: Videos of droplets spreading through air as people talk, a well-intended line of research that has stoked fears about regular human interactions.

Rather, the highest-quality evidence so far is studies like the one published in June in Health Affairs, which found that U.S. states instituting mask mandates had a 2% reduction in growth rates of Covid-19 compared with states without these mandates. Because respiratory virus spread is exponential, modest reductions can translate into large differences over time. But these shifts in trajectory are distinct from the notion that mandating masks will bring the pandemic to an end. Based on evidence around the world, it should be clear that mask mandates won't extinguish the virus.

The most reasonable conclusion from the available scientific evidence is that community mask mandates have โ€” at most โ€” a small effect on the course of the pandemic. But you wouldn't know that from watching cable news or sitting next to a mother being forced off an airplane because her small children aren't able to keep a mask on.

While mask-wearing has often been invoked in explanations for rising or falling Covid-19 case counts, the reality is that these trends reflect a basic human need to interact with one another. Claims that low mask compliance is responsible for rising case counts are also not supported by Gallup data, which show that the percentage of Americans reporting wearing masks has been high and relatively stable since June. Health officials and political leaders have assigned mask mandates a gravity unsupported by empirical research.

On even shakier scientific ground is the promotion of mask use outdoors. One contact-tracing study identified only a single incident of outdoor transmission among 318 outbreaks. Even the Rose Garden nomination ceremony for Justice Amy Coney Barrett, which the media giddily labeled a "superspreader" event, likely wasn't; transmission more likely occurred during indoor gatherings associated with the ceremony.

By paying outsize and scientifically unjustified attention to masking, mask mandates have the unintended consequence of delaying public acceptance of the unavoidable truth. In countries with active community transmission and no herd immunity, nothing short of inhumane lockdowns can stop the spread of Covid-19, so the most sensible and sustainable path forward is to learn to live with the virus.

Shifting focus away from mask mandates and toward the reality of respiratory viral spread will free up time and resources to protect the most vulnerable Americans. There is strong evidence that treating patients early in outpatient settings can be effective, as outlined in a recent American Journal of Medicine paper, but these treatments are underused. Identifying effective treatments for hospitalized patients with Covid-19 is essential, but preventing severe illness before hospitalization will save more lives.

Until the reality of viral spread in the U.S. โ€” with or without mask mandates โ€” is accepted, political leaders will continue to feel justified in keeping schools and businesses closed, robbing young people of the opportunity to invest in their futures, and restricting activities that make life worthwhile. Policy makers ought to move forward with more wisdom and sensibility to mitigate avoidable costs to human life and well-being.

Dr. Ladapo is an associate professor at UCLA's David Geffen School of Medicine.