The SARS outbreak, which hit the world in 2003, presented an opportunity to learn valuable lessons about population health in a pandemic — an opportunity we didn’t really take.

So when COVID-19 came in 2019, we were unprepared, contends Sandro Galea, dean and Robert A. Knox Professor at the Boston University School of Public Health.

At that point, “we were about five decades into a period of neglecting the foundational forces that shape health,” he writes in his new book, The Contagion Next Time. This neglect, he writes, “made us vulnerable to the pandemic.”

And it will make us even more vulnerable to the next.

A physician, epidemiologist and author, Galea — who will be a featured speaker at The Inquirer’s Telling Your Health Story event on Nov. 12 — challenges us to rethink what constitutes health, what promotes health, and how we can get to a healthier world.

He spoke to us recently about the message of his new book.

You say that we now have better medicine than a century ago, but not necessarily better health.

I think the core piece of understanding needed is that medicine and health are different things.

Health is a state of well-being. Health means that we do not need medicine. Health means we can go about our day, realize our promise, and do whatever we would like to do with our lives.

Medicine comes in when we are already sick. In an ideal world, we would not be sick at all. We would continue living long, healthy lives. There is no question that we, as a country, have better medicine to treat disease when we are sick. And that is why we do so well compared with other high-income countries when it comes to the life expectancy of those over age 75. For those over 75, we have very good medicines.

But we fall short in living healthy lives because we fundamentally underinvest in health.

» READ MORE: Register here for free admission to hear Dr. Gallea at The Inquirer's 'Telling Your Health Story' event.

What are some of the key drivers of health?

Our health is driven by the air we breathe, the water we drink, the food we eat, by whether there are conditions that allow us to exercise, whether there is violence around us, whether we have stable housing, whether we have livable wages that allow us to buy the things that protect us from harm, whether we are subject to racism or sexism. That is what drives our health.

That is why an investment in health is an investment in tending to those forces. It is very different from an investment in medicine, which is the drugs and surgical procedures that treat us once we are already sick.

Structural racism and historical injustice are the root causes of our disinvestment in the forces that generate health. One example is redlining, a practice in which red lines were literally drawn on maps around neighborhoods where Black Americans lived. Banks avoided investments in those neighborhoods. Redlining emerged from the Jim Crow era, which in turn emerged from institutional slavery. It resulted in Black Americans having less opportunity to buy homes, which resulted in Black American families having less wealth than white American families today. That has resulted in Black Americans having fewer health-promoting assets. And, as a result, poorer health.

For example, hypertension is higher among Black Americans than among white Americans. Heart disease, higher.

How did COVID-19 expose and exploit those inequities?

COVID-19 exposed the underlying weakness of our social and economic structures. Those manifested not only in overall poor health, but also in health gaps, say, between Black and white Americans.

Just focusing on the health gaps, they were caused by two reasons. No. 1, there was worse underlying health in some groups of Black Americans. And we know that poor underlying health was a major risk factor for death from COVID-19.

No. 2, gaps existed among those with fewer economic and social opportunities to protect themselves from COVID-19. Namely, if your job did not allow you to socially distance, you were much more likely to get COVID-19 than not. Essential jobs and low-wage jobs that require contact with others are disproportionately held by persons of color.

What would a healthier society look like?

A healthier society is one where everyone has the opportunity to live in safe housing, has livable wages, is free from racism, sexism, and other marginalization. It is one where everyone lives in neighborhoods that generate health.

It is one where everyone is educated sufficiently to be able to develop and flourish. Education is the pathway to access a full range of other assets that generate health. It is a pathway to income, to wealth, to stable housing, to living in a neighborhood that is not polluted, to having access to safe transportation, to being away from violence. All of that emerges from education, which is why the universal application of better education can be so important.

That’s what a healthy society looks like.

How do we get there? You say that compassion and humility are essential to helping us achieve a healthier society. How so?

Many in our country value individualism. But in this case, that is predicated on the notion that you can buy your health. When you understand that your health is a product of the world around you, you realize that what wealth can buy you is only care when you’re sick, not health.

When you understand that, in order to be healthy, you need to have a world that generates health, you recognize that you need to have the compassion for everybody’s well-being. Once we have that, we can jointly invest in creating that world.

We have to come to see health as a public good. We have to recognize that your health and my health are produced by the same world. That is what compassion is.

We still need policies, obviously. But to create this kind of world, we need policies that promote these conditions that we are talking about. We need to see all policy as health policy. That alludes to an approach that is called Health in All Policies approach. Policies about transportation, public parks, housing, education, taxation — all should keep public health in mind.

What’s been lacking is compassion. Compassion is saying that I care about your health, not necessarily because I can empathize with you or see the world through your lens, but because of our shared humanity. Hence, I care about a world around you and around me that creates health. A world where there is clean air, stable housing, livable wages and all the other things I talked about — that is what compassion leads us toward. And that is what leads to health.