March 8, 2023

Epidemiologists study patterns of health in populations. Throughout the pandemic, we have relied on their work to understand who is at higher risk for COVID-19 exposure, hospitalization, and death — information that informs the policies created to protect us. Three years in, it has become clear that risk isn’t always patterned by physical characteristics, such as old age or preexisting conditions, but by social characteristics, such as where you live or work.

This can be new territory for epidemiologists who focus on individual risk factors. But as UHC faculty member Alina Schnake-Mahl explains, “If we don’t measure those social, political, and environmental factors, we don’t fully understand the determinants of health and the causes of health outcomes and health disparities, and that those are truly critical to our understanding of the patterns of health.”

We spoke to Dr. Schnake-Mahl and fellow social epidemiologist Dr. Usama Bilal about a recent invited commentary for the American Journal of Epidemiology that offers a roadmap to widen our scope from the individual to the political.

What is social epidemiology, and how does this approach differ from other ways that epidemiologists might look at patterns of health?

Usama Bilal: Social epidemiology aims to uncover how social structures affect health. This includes focusing on how societal systems, instead of individual choices, pattern population health. For example, instead of trying to see whether people who wore masks were more or less likely to have COVID-19 (a very useful question by itself!) we try instead to understand how social conditions drive disparities in COVID-19 incidence by social group. We don’t treat individual risk factors (such as mask use or having diabetes) as something that is independent of who we are, where we live, and how society treats us.

Alina Schnake-Mahl: Another example that has been in the media recently is childhood obesity. You hear a lot about physical activity and the foods that people eat. But the foods that people eat are influenced by societal and economic contexts around them: What food is available is dependent on what’s in your neighborhood, which is dependent on shipping processes, where food is sourced, how much food costs, and if policies incentivize and disincentivize certain food types. All of those factors are critical to the development of obesity and who is measured as being obese and who is not.

How does a social epidemiology perspective change approaches to intervention?

ASM: Current clinical guidelines from the American Academy of Pediatrics say that children should get early interventions that include bariatric surgery. From a social epidemiology perspective, we would say that we need to intervene on neighborhoods and policies. Often those are much harder, stickier problems, and I think that’s part of the reason why we often orient around individual interventions.

In your commentary, you describe a turning point, a few months into the pandemic, when the collective approach turned into an individualistic approach. What happened?

UB: During 2020 especially, there seemed to be a common narrative of "We are in this together." Whether it was purely performative or not, at least some public health actions (e.g. lockdowns, mask mandates) were collective in nature. Once those started to be lifted, we started relying more on "personal responsibility," reflected in masks-optional policies and Test to Treat. That is, by the way, how we normally treat other diseases: we focus on individuals instead of the societal systems in which they are embedded. COVID had, in our opinion, a brief period where that approach was more collective.

ASM: We pretty quickly rejected that notion. Some of that was for economic reasons, which we point to in the paper. There was a direct contrast between public health goals and economic goals. Not to say that economic goals don’t impact public health, because they certainly do, but I think there was a point when we were prioritizing health, and then we said that’s not what we’re going to do anymore.

You also critique the profit-seeking actions of some vaccine manufacturers. Moderna recently announced that it will continue to offer free COVID-19 vaccines to the uninsured after the public health emergency ends. Is that adequate? 

ASM: I think that is allowing a market-based solution when what we actually need are more social policy-based solutions, like paid sick leave. Even if you make vaccines available, that’s not enough, because access and availability are two different things. They are connected systems, and we’re looking at them in isolation. We’re also looking at vaccination as the single intervention we’re willing to continue do at this point. That’s well and good, but, again, we have to think about the larger structures that determine vaccine availability in addition to individuals’ ability get vaccinated.

UB: Is it a good thing? For sure! Should we rely on what is now a multibillion-dollar corporation to decide whether something that is a public good (developed with taxpayers’ money) should be accessible for the population? I don’t think so. We need to take a hard look at how lifesaving developments are treated in terms of regulation and ensuring access. Recent regulations to increase the affordability of insulin would be another good example.

What are the political determinants of health?

UB: The political structures that drive health and health disparities. An example we cite is that of pre-emption, a legislative doctrine that allows a higher level of government (e.g. states) to preclude a lower level of government (e.g. cities) from doing something (or not doing it). For example, many cities were pre-empted from closing indoor dining during the summer of 2020, and we have shown that those cities had higher COVID-19 incidence compared to those that were allowed to close indoor dining. In this example, the political determinants of health wouldn’t focus on indoor dining itself, but rather the political structure of preemption.

ASM: I think the political determinants of health include policy factors, such as how policies like paid sick leave and minimum wage can affect health. During the pandemic, things like vaccination access were certainly on a policy level. But I think it goes further and is also about governance and government structures — the different levels and branches of government and how they intersect with each other and the overlapping power structures that are also important determinants of health and health disparities.

You end with a call for epidemiologists and public health professionals to become more political. Is momentum growing in this direction? Where can we learn more?

ASM: I think a shift is happening in public health, generally, but none of our ideas are new. Going back to theory, Nancy Krieger’s Epidemiology and the People’s Health: Theory and Context is fantastic. I go back to it all the time. There is another book called The Political Determinants of Health, by Daniel Dawes. Throughout the pandemic, Ed Yong really helped to reinforce this collectivist argument and push away from personal responsibility. He framed things well and was a total leader in that space from a journalistic perspective.

UB: “Public health has always been political. Rudolf Virchow, a 19^th century German pathologist, once said, "Medicine is a social science and politics is nothing but medicine at a larger scale." The "de-politization" of public health is, in fact, an explicit political choice to hide the actual determinants of health (e.g., the way the food system is organized) behind what we call “proximal risk factors” (e.g., an unhealthy diet). I highly encourage Danielle Carr’s piece Mental Health is Political.

ASM: It's unbelievably complex, but what Dr. Bilal and I are arguing in part is that questions about government and policy are not outside of epidemiology — they should actually be core questions. Understanding governance structures and other complex systems that determine city, county, and state power are important for us as epidemiologists to understand.