How to Talk about the Balance of Benefit and Risk in Public Health Interventions

April 29, 2021

Focus on the destination, not the seatbelts.

Eric D. Perakslis, PhD


Imagine visiting the local pub and sitting next to a hobbit, recently arrived via wizard from Middle Earth, who has never seen an automobile. This polite fellow, who is fascinated by the cars driving by, is full of questions about them. How do you begin to answer him?

Front view of the Eagle and Child pub in St Giles Street, Oxford. The pub was a favorite meeting place of the group of authors and Oxford professors known as “the Inklings” – JRR Tolkien, CS Lewis, Hugo Dyson, Charles Williams, and others. Image credit: Ozeye via Wikipedia (CC BY-SA 3.0)
The Eagle and Child pub in Oxford, UK. If you are ever to meet a hobbit in a pub, it would most likely be this one. Image credit: Ozeye via Wikipedia (CC BY-SA 3.0)

Would you begin by talking about seatbelts? They are, of course, an essential part of modern cars. They protect passengers from being ejected from the vehicle during an accident: drivers who wear them are 44% more likely to survive a crash than those who do not. In 2017 alone, seatbelts saved an estimated 14,955 lives. But despite massive amounts of evidence to the contrary, some still assert that seatbelt use is actually dangerous, contending that wearing one may trap you in a fire after a crash or cultivate a false sense of security that results in riskier driving.  At this point in the conversation, the hobbit, by now missing his trusted pony Bumpkin even more, politely changes the subject.

Almost all human endeavors—at least the fun and important ones—entail some degree of risk.  Many of these more common risks are understood at some level by everyone, regardless of education or expertise. People drive and fly every day knowing that cars and planes may crash.  People flock to the waterfronts and swimming pools of the world, yet drowning is the third leading cause of unintentional injury death globally according to the World Health Organization (WHO). This may have been a convincing statistic for our hobbit (who greatly enjoys the swimming holes in Eastfarthing) had the teller had the statistics handy, but maybe not. Looking out the window of the pub at the snarled traffic and careful pedestrians, our hobbit friend may have simply declined to consider automobiles further.

More than a year into the COVID-19 pandemic, public messaging, especially concerning the relative balance of benefits and the risks associated with measures such as mask wearing, COVID testing, and vaccination, remains challenging and contested. This is partly due to the complexity of talking about benefits and risks of health interventions, and partly because many of the messengers are themselves unsure. 

While well-known statistics about long-studied topics such as the risks and adverse event rates of anesthesia are confidently cited thousands of times daily by medical professionals, patients, and caregivers, information about COVID-19 vaccines is another story altogether. These medical marvels were developed at breakneck pace and authorized for emergency use following an abbreviated process of regulatory review. Along the way, every twist and turn of the story has been covered ad nauseum by mainstream media, but has received even more attention from disinformation outlets and the antivax movement.

Given scientific uncertainties and a roiling public debate, is it reasonable to expect a suspicious, polarized, and frightened public to understand and rationally weigh risks and benefits in such circumstances? 

In a sense, the answer to this question is neither here nor there. The fact is that people are already making their own decisions on the balance of benefit and risk daily, regardless of what information they have to buttress those decisions. A better question might be: How can we as medical and policy professionals help people make the best decision for themselves, even if that decision differs from our “expert” opinions—opinions that, given a proper dose of humility, may also need some adjustment and fine-tuning?

First, we must understand that determining benefit and risk requires complex math. So complex, in fact, that quantitative evaluations of benefit and risk are rare, even in regulatory agencies. Nevertheless, keeping a few key concepts in mind can help. One of the best ways to understand complex mathematical situations is to think in terms of boundary conditions.  Simply put, these are known quantities that exist at the extremes of any mathematical system, such as the velocity of an object at rest being equal to zero.

When we apply this concept of boundary conditions to medicine, we can see how important it is to thinking about benefit and risk. At the same time, we must also understand that humans do this instinctively in their head many times in the course of a day—and the results are not always what we might expect or hope. For example, cigarette smoking offers zero medical benefit and a very high degree of risk, yet many people still smoke. In the context of the COVID pandemic, wearing a face mask is thought to have tremendous potential benefit and virtually zero risk, yet many refuse to mask.

...we must not assume that a relative reduction in risks equates to a perceived increase in benefits. It does not, even when describing preventative interventions such as vaccines.

Guided by these examples of medical boundary conditions, we can see a path forward, but it will not be easy. Acceptance of public health messaging depends on a shared perception that the benefits of an intervention outweigh any associated risks. Importantly, though, we must not assume that a relative reduction in risks equates to a perceived increase in benefits. It does not, even when describing preventative interventions such as vaccines. What good is being vaccinated if I still cannot visit my parents, or sit in a restaurant with vaccinated friends for more than an hour? Why should I comply, when so many others are not?

Picture of two Black men, both wearing colorful print shirts, hugging. Image credit: Erika Giraud via Unsplash
Image credit: Erika Giraud via Unsplash

The key to balancing this equation—engendering trust even while we work amid uncertainty—lies in doing a better job of quantifying both sides of the benefit-risk ratio. When benefits are described, they must be clear, believable, trustable, and, most importantly, compelling if we want people to act on them. The recent announcements from the Centers for Disease Control and Prevention easing outdoor restrictions for vaccinated people are a great start, especially the excellent visualizations, but more is needed, especially local nuances and consistency. Challenges calling these new measures too timid and too complicated are not completely wrong. We should be talking about getting back to 100% in-person K-12 education via complete vaccine protection, strong testing regimens, syndromal surveillance, and a less polarized, more unified vision of community.  We should be talking much more about preventing loneliness, depression, and suicide. We should be talking about singing in church, about hugging our friends and family, about shaking our neighbors’ hands. 

To put it another way: we should be talking about the pleasures of a leisurely Sunday drive, then and only then should we mention seatbelts. For the most part, the public is out of time and out of resolve to simply hunker down and “do the right thing” – especially when the “right thing” can seem like a moving target. And the more we talk about the seatbelt as the most important element of the automobile, the more we will continue to be drawn into countering spurious arguments, sometimes advanced in bad faith, that seatbelts cause drowning when cars become flooded.

Instead, we must resolve to sharpen our depictions of the risks and benefits associated with various behaviors during the second year of this pandemic. With 25% of the adult population in the US fully vaccinated and half of adults having at least one jab, are our proposed measures balanced and objectively quantified? If not, on what are we basing our decisions?  If we need to run a study to find out, then let’s run that study. Initiatives such as the $1.5 billion the Biden administration is allocating for vaccine confidence are essential, but a significant proportion of these funds must go to develop newer, better, and analytically measurable impacts on public opinion and behavior. 

Further, part of the approach must include intentional countermeasures to combat organized disinformation. Efforts such as the Covid Disinformation Toolkit created by the Cybersecurity and Infrastructure Security Agency (CISA), while useful, are at best rudimentary. We need more tools and we need more “teeth,” including offensive measures to be deployed in circumstances where truly malfeasant disinformation gains ground. This will not prevent disinformation campaigns but it will diminish their effectiveness.  

Given no pony in sight and a long way yet to go, I decide to drive my hobbit friend to his inn for the night. I had a bit of trouble getting the seatbelt to fit the little guy and he kept trying to stand on the seat so he could look out the windows. I hadn’t thought about how the seatbelt would reduce his enjoyment of the ride by preventing him from seeing out of the windows.  I guess I got the math wrong again. 


Cover art for the book Digital Health: Understanding the Benefit-Risk Patient-Provider Framework by Eric D. Perakslis and Martin Stanley.

Eric Perakslis, PhD, is the Chief Science and Digital Health Officer for the Duke Clinical Research Institute and co-author with Martin Stanley of the book Digital Health: Understanding the Benefit-Risk Patient-Provider Framework. To read more blog posts from Eric Perakslis, click here.

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