Public health — the science of protecting and improving the health of a population — includes everything from setting pollution limits to urging women to get mammograms. It’s investigating salmonella outbreaks, tracking Lyme disease, defining drunk driving, fighting climate change, tackling systemic racism, inspecting restaurants, distributing condoms and every other activity that affects health.

This broad array of activities reflects our modern-day understanding that myriad factors influence people’s health. It’s a long evolution from public health’s origins, which were squarely focused on fighting infectious diseases, starting with the bubonic plague in the 1300s. Things that many people take for granted, like clean drinking water and garbage collection, exist because of public health. And to this day, success with cholera, smallpox, polio and other once-rampant diseases are still considered some of its biggest wins, says epidemiologist Ross C. Brownson of Washington University in St. Louis.

But then — what happened with Covid-19? The US accounts for a bit more than 4 percent of the world’s population but has seen nearly 20 percent of global Covid-19 diagnoses, making the US pandemic experience an epic public health failure.

The immediate culprit is politics, says Brownson, associate editor of the Annual Review of Public Health. Conflicting and sometimes inaccurate messages from politicians prompted many Americans to mistrust science-based advice about how to stay safe. But more important still, he says, may be that people don’t know what public health is, let alone appreciate its importance. And, as a consequence, we have been under-investing in it for years.

The silver lining of Covid-19 may be that more people finally are beginning to learn about public health, Brownson says. In an interview with Knowable Magazine, he explains why the renewed focus creates opportunity even during this time of crisis. This conversation has been edited for length and clarity.

Is America’s public health system set up in the right way to fight Covid-19?

The lead public health agency for the country is the Centers for Disease Control and Prevention in Atlanta. It’s one of the top public health agencies at a national level in the world, and it has a big footprint in global work, especially around infectious diseases. Then we also have state health departments and about 3,000 local health departments at the city and county level.

In the first month or so of Covid, the President said, “We’re going to war against the virus.” Imagine if we were in World War II — would we leave it up to each state to decide how it’s going to fight that war? Each state or local jurisdiction is going to be in charge?

The CDC is highly qualified to direct what a national strategy would be. They know how to put a surveillance system together; then they could send their guidance and funding to the state and local agencies. But if the political arm doesn’t allow the scientific arm to do its job, what we have is a muddled mess.

What is a surveillance system?

It’s the data system that really drives public health. One example is the surveillance system for a vaccine-preventable disease like measles or mumps. Doctors are required to report any cases of those diseases to the local public health authority, which sends the information up to the state, which sends it onto the national level. It becomes an early warning system to identify when there’s a spike in the disease that needs to be addressed.

We have surveillance systems for all different kinds of diseases, including cancer. Also, we have surveillance systems for foodborne illnesses and other health risks. Local public health agencies report those up the line, and the CDC has epidemic intelligence officers who go in and track down where the problem came from.

That sounds like a lot of work.

Surveillance is not the most glamorous part of public health, but we have a saying: What gets measured gets attention. So when we are measuring what’s going on in a community — a disease or a risk factor such as the presence of dangerous ticks or mosquitoes — and analyzing it on a regular basis, we can take public health action when we need to.

How has the surveillance system for Covid-19 worked?

For a pandemic like Covid, surveillance should start with having a reliable, valid test for the virus and a plan to roll out that testing across the whole United States. A plan should guide us on which populations are high-risk and where we need to prioritize our efforts. It would also set out the best way to test people who do not have symptoms, determine how long people should quarantine after they have been exposed to Covid, and address all the other issues that public health experts know how to deal with.

In the case of Covid-19, surveillance worked inconsistently because it was largely left up to the state and local governments. And that’s a problem, because capacity is diminished due to decades of underinvesting in public health at those levels.

Underinvesting? We often hear that the US spends more on health care than any other country.

The country’s total health care spending is greater than that of any other nation by far, but that is mostly for medical care. Less than 3 percent of our total health care spending goes for public health, and that percentage has been shrinking.

Public health agencies at the state and local level used to receive much more funding from the federal government — grants made from the CDC — and that gave them stability to plan and prepare for crises. The federal share of total public health expenditures was 50 percent in the 1970s, and now it’s down around 13 percent or so. And it’s not distributed equally.

Since there is not a consistent federal investment at the state level, each state is left on its own. Some states have a dedicated revenue stream that goes directly into public health. In others, public health is competing with every other function of state government and it doesn’t always come out ahead. Alaska gets $281 per capita in state and federal dollars for public health, and Nevada gets just $46.

Local health departments — responsible for a county, city, public health district or other local jurisdiction — lost more than 50,000 staff positions between 2008 and 2017. Where the rubber hits the road is at the local level — that’s really the frontline of public health. And that’s probably where we’ve seen the greatest deficiencies and the underinvestment in this Covid pandemic.

Bar graph shows jobs lost in local public health departments for years 2008-2017; in 2009 alone at least 16,000 jobs were lost.

Local health departments in the United States, which provide health-related services including addressing opioid use, flu outbreaks and food insecurity, have been hollowed out by years of staffing cuts. These departments eliminated 56,360 jobs in the decade that ended in 2017.

Looking at our Covid-19 death toll, that seems pretty short-sighted.

When public health is working well, it’s invisible, because people are healthy and safe. For example, there were years of scientific research by public health agencies that led to the laws that require seatbelts, and lots of public awareness campaigns funded by public health agencies. But you don’t get in your car and think, “I know there’s a public health law about this, so I’ll put on my seatbelt.”

When we have financial challenges — for example, the recession that started in 2008 — we make budget cuts and then people gravitate toward a new normal and say, “Well, the world hasn’t fallen apart. We seem to be doing OK.” Then policymakers tend to put money into something that’s more visible — roads or a new hospital — rather than in these behind-the-scenes backbone investments that are needed for state and local public health.

The pandemic has pulled back the curtain on that underinvestment and really ought to give us an opportunity to plan and do something different going forward.

Opportunity? This feels like a crisis.

Media use of the terms “public health” and “epidemiology” in January through May of 2020 — compared with the same period in 2019 — increased a thousand-fold. If we can harness this knowledge and interest in the value of public health, then I think we can be cautiously optimistic long-term.

Two line graphs show that more local health departments have reported budget cuts than budget increases in the years 2008-2018.

Year-to-year budget cuts are common for local health departments, which may have to divert resources slated for specific services to other programs when budgets are tight.

Is more money the main fix?

The most important thing is communicating the message that public health is a common good and we need to support it as a common good. We have unacceptable health disparities in our population — racial disparities, disparities by income group and others. These show up in our Covid deaths, but they are evident in all manner of health conditions.

We are the richest country in the world and we spend, by far, more on health care in the United States per capita than any other place in the world. So the money is in the system and we have some of the best scientists in the world. We can solve any problem the world sends our way, but we need leadership and political will.

Leadership really starts at the national level, but the kind of leaders we need right now are found largely at the state and local levels. I put New York Gov. Andrew Cuomo in that group — someone who relies on scientific evidence to make decisions and has the political will to take on an issue and sometimes make the unpopular decision when it’s the right decision.

What else?

We need to modernize our surveillance systems. In Wuhan, China, they are using artificial intelligence to map where the epidemic is and where it’s going. In some parts of the world, cell phones are part of the surveillance system. If you’ve been tested for Covid and you’re symptom-free, you get a green light on your phone. If you’re coming into contact with someone who has not been tested, a warning device on the phone will alert you. Other data displays (or “dashboards”) might show Covid risk in your county or city.

We also need to update the way we think about and address risk. Rather than just saying that an unhealthy diet is a major risk factor for heart disease, we need to look at the underlying reasons for unhealthy diets. People living in a low-income community may not have access to healthy food, so even if they want to eat a healthy diet, they can’t do it. Inequalities are so prominent in our society. What public health calls the “social determinants of health” — such as education, poverty, neighborhood environments, and racism — are at the root of many health inequities, including those we’ve seen in Covid.

Also, we need a new set of communication skills for public health professionals. This includes how we communicate with policymakers and how we communicate risk to the public. Marketers know about audience segmentation, and we could learn a lot from the private sector about how to reach specific audiences. We know that if you perceive yourself to be at risk, you’re much more likely to take action — that’s why the message about masking to prevent Covid works well for people who are over 65. But younger people are less susceptible to a serious outcome, so the messaging needs to be different for them. We also need to spread those messages to where the different audiences are likely to get their information and have them delivered by trusted peers.

One of the biggest challenges in communication is figuring out how to counter misinformation quickly and effectively. That has been an issue with things like the anti-vax movement, but Covid has lit a match on this powder keg of misinformation. The inaccurate messages from leaders coupled with a growing skepticism of science create major challenges as we go forward.

This article is part of Reset: The Science of Crisis & Recovery, an ongoing series exploring how the world is navigating the coronavirus pandemic, its consequences and the way forward. Reset is supported by a grant from the Alfred P. Sloan Foundation.