When public health educators talk about their field, they often start with John Snow and the pump handle.

It was 1854, and London was experiencing a cholera outbreak. Many thought the culprit was miasma — bad air. But Snow, a physician, suspected the water. At the time, people got their water from various public wells, operated by hand pumps. He looked at all the people who were infected and realized they were all getting water from one particular well.

The pump handle was removed. People switched wells. Outbreak over.

Laura Siminoff, dean of Temple University’s College of Public Health, loves this story. It epitomizes what public health is all about.

The role of public health has certainly changed since the days of public pump handles. And it is poised to change again, as we face climate change, new pandemics and an aging population. It will require changes in the public health workforce.

But its core mission, promoting the health of communities, will remain. We spoke to her recently about where we’ve come from, and what’s ahead.

What, exactly, is public health and how has it changed?

Public health is the safeguarding of population health. Public health is the collective health.

COVID-19 is a great example. Yes, individuals got infected. That was individual health. But we also saw that those infections were dispersed within populations in really different ways. For instance, we saw that people who lived in congregate settings were more likely to get sick and die.

What we understand about public health now is that people are not islands. They live in communities. Public health has to address their living conditions, the way they can or cannot access health care, the way the entire health-care system responds to them.

Clearly, public health deals with disease. But it is also highly focused on prevention. The goal of public health is to keep populations as healthy as possible.

It has changed over the years because there’s been a shift in what causes death in this country. A hundred years ago, chances are you would die of some sort of infectious disease. Then came penicillin, clean water, pasteurized milk. Now, chances are you will die of a chronic disease. Chronic disease is a much more complex mechanism. It’s an interplay of your biology, your physical environment, your social environment, your economic environment.

So public health isn’t just about bugs and water anymore. It’s about systems. It’s about the structures within which human beings live together as individuals and as groups.

What changes do you envision?

I think there are a lot of changes on the horizon for public health.

We need to move toward a much better understanding of the interplay between biology and environment — your social environment, your physical environment, and so on. This has to be the future of public health.

Going forward, we have to look at all the different components that contribute to the health of individuals and populations. Housing is very important. Urban policy is very important. Look at gun violence. It is a major cause of mortality [especially] among young men. So it becomes a public health issue. But it’s also an issue for social work and for a lot of other public health-related disciplines. The opioid epidemic is another example showing how all the health professions need to work together to solve complex problems.

One of the major challenges going forward is climate change. I’m stunned at the weather. Philadelphia is starting to look like Atlanta. That has major implications for people’s health. It is something we will have to address.

We’ll have to deal with changing demographics. Our population is aging. That will present a major challenge.

We are also becoming more urban. This is a concern because it is associated with different health problems for people and requires different interventions. For example — and this is where public health officials could work with architects — people become sedentary when they live in these big urban conglomerates. They are in areas that are not walkable or don’t offer other exercise opportunities. This means that they suffer more from many of the chronic illnesses that kill people these days. Heart disease. Stroke. Diabetes. These social behavioral habits — driving instead of walking — are of great concern for public health. Understanding behavior is critical to designing public health interventions.

Sometimes people say, “well, is everything public health?” And I answer, “Sort of.”

How will the workforce have to change?

First of all, we need a much more diverse public health workforce.

We need a far more professional, well-trained public health workforce. There’s been a blossoming of public health bachelor’s degrees. That results in a much better-educated workforce for state and local health departments and all the other organizations that deal with public health issues.

But we need to work in a much more interdisciplinary way to safeguard people’s health. There’s always been a stark divide between public health disciplines and the clinical fields such as medicine, nursing, physical therapy. I think it’s no longer a useful division.

Another part of the future of public health is data, health analytics, and health informatics. This includes things like electronic health records and how we can use data from them to examine trends, detect outbreaks. It can also provide data to help structure the health-care system to be more efficient and effective.

We also recognize that we need a workforce that’s trained in strategic skills — things like systems thinking and policy engagement and problem solving and data analysis. We need our public health interventions to be evidence-based.

Our public health workforce has to be prepared to be leaders and to think about systems.

What about public health funding?

The gross underfunding of our public health infrastructure is one of the reasons that we had so much trouble responding to the pandemic. Funding hasn’t increased since the mid-’80s. Among states, Pennsylvania ranks 41st in funding. So, there are only nine other states that fund their public health system as poorly as we do.

Delaware County doesn’t even have a health department. So they had to go to Chester County for assistance. They also came to the college for assistance with contact tracing, and we helped them. But you shouldn’t have an entire county that doesn’t have a health department.

[Editors’ note: Delaware County is now forming its own health department and expects it will open by January.]

If you look at the way information was being put out by different states, you could see the difference. New York poured enormous amounts of funding into discovering where the hot spots were and gathering other data. Their website was easy to understand and it was easy to search. But with other states’ sites, if you didn’t really stick to it and you weren’t really good at looking at data, it was hard to find information.

The current administration is putting more money into public health, but we need still more.

What else do you see when you look at the future?

We need to see public health not as just a local affair, but as a national affair. If we had approached COVID-19 as the national emergency it was, with all of us doing things together to mitigate the epidemic, we would not have suffered as much as we have, as a nation.

In World War II, they rationed things, they had drives to collect metal. They didn’t do it state-by-state. It was a national effort.

If we had responded to COVID-19 in a unified way, hundreds of thousands of lives would have been saved and we would have been able to open up and get our economy on track much sooner.

Overall, we need to rethink our responses to health-care emergencies. It is not just individual health. It is population health.