Just over a century ago, a virulent flu outbreak was wreaking havoc on the world.
We know it now as the 1918 influenza pandemic, and its tremors were felt far and wide. By the end of its spread, tens of millions were dead.
The field of public health has taken a giant leap from the days of 1918, when virology was still in its infancy. Today, information is instantaneous and vaccines are in widespread use.
And yet we find ourselves in an oddly similar moment in which experts are recommending many of the same, old-fashioned measures enacted to stem the 1918 epidemic.
NPR's Short Wave podcast sat down with medical historian Dr. Howard Markel, director of the Center for the History of Medicine at the University of Michigan, to hear what the world of 1918 can teach us in 2020.
This interview has been edited for length and clarity.
What has the world been like for you these days? What has it been like to live through this pandemic?
It's been amazingly busy. When you're a historian of quarantine and epidemics and a worldwide pandemic occurs, it's sort of like ... being an accountant during tax season. And it's been especially busy because our center did a great deal of work with the CDC on these issues of social distancing and flattening the curve by looking at examples in the past where social distancing measures helped to save lives. ... But I was much more comfortable thinking about them in my head than seeing them enacted around the country [and] around the world!
It's like you're finally living what you've been researching for years.
Even when you're thinking about worst-case scenarios — like the most terrible pandemic ever — you're thinking about it [and] you're planning for it, but you're not living it. Seeing all of my work come to fruition is really gratifying, because ... I know it is helping to reduce the death rate, but it's also horrifying, because it means that there is a worst-case scenario pandemic going on.
One of the things that we want to talk to you about today is the 1918 influenza outbreak as the biggest pandemic in history. What was that period like?
It is helpful to look back at  because, as you say, it was the worst pandemic in [recent] human history. ... Even though it was the 20th century, there was very little that doctors could do for their patients in terms of interventions. There were no medicines that really helped influenza patients. There were no IV fluids. There were no respirators. There were no vaccines.
On the one hand, we've come such a long way in terms of modern medicine, but on the other hand, we didn't have a vaccine then and we don't have a vaccine now.
In a way, we're kind of pulled back to the 1918 era, because not only do we not have any vaccines, we [also] don't have any effective antivirals that could treat people who get sick. On the other hand, we have intensive care units with ventilators and all sorts of machines that could measure oxygen content in blood, and all sorts of other things that allow for the care of the very, very acutely ill. ... But there are similarities in that we just don't know what to do right now.
What we are doing are really old-fashioned public health measures. We're actually hiding from the virus by doing these social distancing measures, hoping to buy time to a point where a vaccine may be ready.
How does it feel to see these kinds of old-fashioned measures being practiced today?
What's terrific about it, at least where I live, is how well people are adapting. And, you know, when we were proposing these measures about 15 years ago, there were a great many critics. People said, you know, life will end as we know it. [These measures] will destroy the universe ....
Of course, it's not destroying the country. And even though the economy has been very heavily disrupted, I don't deny that, I'm positive that we'll get back to life after this dies down. Societies have dealt with terrible pandemics almost since there's been human beings, so history is on the side of resilience and coming back.
One thing that your research has really focused on when it's come to 1918 is that the cities that really embraced social distancing came out stronger. Is there a lesson to be learned from that at the moment we're in right now?
There's two lessons.
One, "early, layered and long" works. It's not just 1918. We saw it in Mexico in 2009 [during the swine flu outbreak], and we've seen it elsewhere in experimental or modeling studies. We are certainly seeing it today in many countries and locally in many states.
The second lesson is that in 23 of the 43 [U.S.] cities we studied, [people in 1918] got restless after a while. They wanted the social distancing measures released; they wanted to go back to their normal lives. If you looked at the epidemic curve, it looked as if the cases and deaths were falling.
But if they weren't falling enough — if they weren't low enough — and then you open things up, the virus was still circulating and you got a second hump to [the epidemic] curve and another upward tick in cases and deaths, sometimes worse than the initial hump of their epidemic curve.
So what you're saying is that the shape of the curve can really follow the behavior of individuals.
Epidemics are living social laboratories. They involve many, many actors, not least of which is the microbe in question. Different microbes do affect people in different ways. They like different types of weather conditions. Different people behave differently before an epidemic, than during an epidemic, [and] in the middle of it, when they're tired of it. And this is why I'm a little bit skeptical of many mathematical models of epidemics, although they are helpful as one piece of data, but not the entire story.
And in that way, we're almost in uncharted waters, unexplored territory, even using 1918 as a benchmark.
1918 is so vastly different.
We're using it as a benchmark because ... it's what the worst-case scenario [is] and we have a lot of data on it. But the country is different [now]. Our transportation is vastly different. We have connectivity in a way that people couldn't even dream about in the form not only of telephones and smartphones, but the Internet. We have social media so people could tell their stories in ways that they could never communicate back in 1918. But we also have a leadership situation that has never been seen before.
So, yeah, historians are going to be busy on this one for a long time to come.
This episode was produced by Brit Hanson and Berly McCoy fact-checked. Viet Le was the editor.