Public Health Is Personal

I have been thinking about public health lately. It seems like an important topic to understand, particularly because public health—and the people and institutions responsible for it—have been the focus of recent news. With so much information, misinformation, and sometimes just plain confusion circulating about health and healthcare, I thought it might be helpful to take a step back and look at what public health actually is, what it does, and why it matters.

Public health has been part of my life for as long as I can remember. My mother was a microbiologist who worked in public health, so I grew up with an appreciation for the science behind disease prevention and for the many ways health is influenced by factors beyond what happens in an exam room. As a physician and now as an integrative health and wellness coach, I have come to appreciate this even more. Our health is shaped not only by our individual choices, but also by our relationships, our communities, our environments, and the systems in which we live.

What exactly is public health?

Medicine often focuses on the health of one person at a time. Public health focuses on the health of populations.

That can encompass a remarkably broad range of activities: tracking infectious diseases, ensuring the safety of our food and water, monitoring environmental hazards, promoting vaccination, studying patterns of illness and injury, developing recommendations for disease prevention, preparing for emergencies, improving maternal and child health, addressing substance use, reducing tobacco-related disease, and identifying the social and environmental conditions that influence health.

In a sense, public health asks a different question from the one we traditionally ask in a doctor's office. Instead of only asking, "How do I help this person?" public health asks, "What can we do to help prevent illness and promote health across an entire population?"

That is a much more complicated question.

In the United States, this work also takes place within a culture that places a very high value on individual rights and personal choice. Those values are an important part of our history and our identity. At the same time, there are circumstances in which the health of one person can affect the health of many others.

Vaccination is a straightforward example. When we vaccinate a child, we are protecting that child from potentially serious disease. We may also reduce the likelihood that the disease will spread to others who come into contact with that child, including infants who are too young to be vaccinated, people with compromised immune systems, and others who cannot safely receive certain vaccines.

This is one of the fundamental concepts of public health: individual health and population health are often interconnected.

The science is always evolving

Another important thing to understand about public health is that it is grounded in an evolving body of scientific evidence.

This is true in public health just as it is in medicine.

What we understand at one point in time reflects the evidence available to us at that point in time. As new information becomes available, our understanding can change. A larger study may provide a different answer. A new technology may allow us to measure something we couldn't measure before. Researchers may identify a previously unrecognized risk or discover that an intervention works differently than they initially thought.

Changing our understanding in response to new evidence is not necessarily a weakness of science. It is one of its defining characteristics.

I remember learning this early in my medical training. Medical recommendations are not permanent declarations of truth. They are conclusions based on the best available evidence at a particular point in time.

This became especially apparent during the COVID-19 pandemic. Public health officials were making decisions about a new and rapidly changing infectious disease while working with incomplete information and enormous uncertainty. Recommendations evolved as researchers learned more about how the virus spread, who was most vulnerable, how effective different interventions were, and how immunity changed over time.

With the benefit of hindsight, it is easy to look back and identify things that could have been done differently. That kind of reflection can be valuable. It is part of how science and public policy improve.

But there is an important distinction between thoughtfully evaluating a decision based on the evidence available at the time and judging it solely through the lens of what we know now.

The former can help us learn.

The latter can make it much harder to understand what actually happened.

The people behind public health

It is also worth remembering that public health is not an abstract institution. It is a field made up of people.

Epidemiologists, physicians, nurses, microbiologists, statisticians, researchers, environmental health specialists, educators, policy experts and many others work in public health. Their responsibilities can range from monitoring disease outbreaks and conducting research to developing prevention strategies and communicating health information to the public.

Like people in every other profession, they bring different experiences, perspectives, strengths and limitations to their work. They can make mistakes. They can disagree with one another. They can communicate imperfectly. And sometimes they can make decisions that, with additional information, they might make differently today.

That is not unique to public health.

The challenge is that decisions made in public health can affect millions of people, which means the consequences of uncertainty can feel particularly significant.

Ideally, the people working in this field should be knowledgeable, thoughtful, ethical, transparent about what they know and don't know, open to new evidence, and willing to revise their thinking when the evidence warrants it. High standards—but also reasonable ones for any field responsible for helping protect the health of others.

The remarkable things we have accomplished

Sometimes I think one of the challenges of public health is that its greatest successes are almost invisible. When public health is working well, nothing happens. A child doesn't get polio. A community doesn't experience an outbreak of measles. A family can  turn on a faucet and trust that the water is safe. A restaurant follows food-safety standards and no one gets sick. An infectious disease is identified before it spreads widely. A public health campaign helps people stop smoking. A vaccine prevents an illness that we never have to think about.

These successes can be easy to overlook precisely because they don't feel dramatic. But the evidence of what public health has accomplished is extraordinary.

A 2020 study published in Health Affairs examined the reasons behind changes in U.S. life expectancy between 1990 and 2015. The researchers estimated that 44% of the improvement in life expectancy during that period was attributable to public health, compared with 35% attributed to pharmaceuticals and 13% to other medical care.

And consider vaccination. A 2024 analysis published in The Lancet estimated that global vaccination programs against 14 diseases had averted approximately 154 million deaths over the previous 50 years, including 146 million deaths among children under five. The researchers estimated that vaccination accounted for roughly 40% of the observed decline in global infant mortality during that period.

Those numbers don't tell us that public health is perfect. But they do tell us that public health works.

Holding two things at once

Perhaps what I am hoping for is that we can become a little more comfortable holding two ideas at the same time. We can acknowledge that public health officials can make mistakes and recognize the enormous value of public health. We can question recommendations and respect the scientific process behind them. We can recognize that recommendations sometimes change without concluding that everything we were told before was a lie. And we can value individual freedom while also recognizing that our individual health is connected to the health and wellbeing of the people around us.

That last piece is particularly important to me.

As an integrative health and wellness coach, I spend a great deal of time talking with people about the interconnected nature of health—our bodies, our minds, our relationships, our environments and our communities. Public health asks us to expand that circle even further.

It asks us to think about us. Not just my health. Not just your health. But the health of the community we share.

That doesn't mean every public health recommendation will be right. It doesn't mean every policy decision will be wise. And it doesn't mean that public health officials should be beyond questioning.

It means that making decisions for an entire population is extraordinarily difficult work. The variables are enormous. The evidence is imperfect. The stakes can be very high. And the people making the decisions are human. Perhaps what we owe them isn't unquestioning trust. Perhaps what we owe them is something more reasonable: curiosity, scrutiny, humility, and a willingness to recognize how difficult the work actually is.

Because for all of its imperfections, public health has helped create a world in which millions of people live longer, healthier lives than generations before us could have imagined.

And that is worth appreciating.