The number of coronavirus cases has overtaken that of the 2003 SARS epidemic. Officials and scientists are racing to track the path of the virus and develop a vaccine. Twenty-two countries have reported finding people sickened with the virus. The WHO has announced a “public health emergency of international concern.”

We’re in a relatively new era of infectious disease outbreak, said prominent science journalist Sonia Shah. Diseases are sequenced faster and tracked more accurately than ever before – but they also arise more frequently, as humankind and nature collide often and with greater intensity.

Shah knows her way around infectious disease outbreaks – along with the public health, epidemiology, and social consequences surrounding them. She’s the author of the 2010 book The Fever: How Malaria Has Ruled Humankind for 500,000 Years, along with 2016’s Pandemic: Tracking Contagions from Cholera to Ebola and Beyond.

She sat down with Direct Relief this week to talk about the likely scope of the coronavirus outbreak, the public health response – and the potential impacts.

Direct Relief: Your book, Pandemic, is a look at the major contagious disease outbreaks of modern history, including Ebola, MERS, and SARS. Considering what you’ve seen so far, how does the new coronavirus outbreak compare to other infectious disease outbreaks – in transmission, scope, or public perception?

Shah: It’s obviously one that’s causing a lot of alarm, and there’s been a very vigorous public health response, so in some ways that makes it unusual. There are a lot of outbreaks of a disease where you don’t see a big public health response, so I think that’s actually a positive.

China is doing a lot to contain it. And I think you can debate whether all those measures are worthwhile or not, but there’s no lack of attention to this outbreak.

Direct Relief: How are the epidemics of modern history different from those of, say, the 1918 Spanish influenza pandemic? Why are there more frequent disease outbreaks, and what are the challenges of fighting them in the modern world?

Shah: About 60% of these new pathogens that we’re seeing, that have come out in the last 50 years or so, they derive from the bodies of animals. About 70% of those derive from the bodies of wild animals.

And that’s because people and wild animals are coming into novel, intimate contact. That allows the microbes that live in their bodies to cross over into our bodies.

Ebola, Zika virus, SARS, West Nile virus – there are any number of novel pathogens that have emerged in the past few decades that come from the bodies of animals.

Animals and people are coming into new kinds of contact because of a variety of reasons, the biggest one being that we are essentially destroying so much wildlife habitat.

What that means is a lot of animals are going extinct, but the ones that remain have to crowd into ever-tightening little patches of habitat that we leave for them. That’s more frequently not in some distant, intact forest. Instead, it’s our farms and gardens and our towns and cities.

Direct Relief: Are we better at fighting infectious disease over the past couple of decades?

Shah: I think there are some ways in which we’re getting better. The fact that we had a diagnostic for this new coronavirus so fast, that’s amazing, and that means that you can track it.

I think in terms of scientific collaboration, discovery of how these pathogens work, diagnostics, and genotyping, those are happening a lot faster now as the technology gets better. We just have so much more knowledge.

But then I think there are valid questions to be asked about whether we’re using that knowledge effectively. Just because we can know that this novel coronavirus is causing this pneumonia – not some other pathogen – is that actually helping us to contain it, or not?

I don’t think we know the answer to that question yet, and we won’t for some years, until after this whole thing blows over and we have time to analyze how it went down.

We saw this in Haiti with the cholera outbreak after the [2010] earthquake. Cell phones were relatively new at the time and it was possible for people to map how cholera was spreading just based on cell phone data.

They could see, “OK, it’s coming down this road, it’s going to be going down this trucking route, it’s probably going to lead to this village in the next week or two.”

All of that…was amazing, scientifically, but it didn’t actually help anyone prevent cholera from breaking out. We knew it was coming, but it happened anyway.

Direct Relief: Why do you think this virus has inspired such a media frenzy and such widespread fear?

Shah: I think there are some good reasons. One is that it’s similar to SARS – it’s a coronavirus, like SARS – and we know that SARS was very virulent and it spread pretty well and it got pretty far. It got to dozens of countries really rapidly and killed 800 people, and this virus is in the same family.

That said, it’s a pretty big family. There are some coronaviruses that are very mild and some that are very virulent, so just the fact that it’s in that family of viruses doesn’t necessarily mean that it’s going to kill a lot of people.

And I think the other good reason is that it’s respiratory. There isn’t a lot of evidence that we know how to control the spread of respiratory illnesses. Seasonal flus every year take out hundreds of thousands of people.

We try. We have vaccines, we tell people to wash their hands, we tell people to stay home when they’re sick. Do they make any headway at all? It’s hard to know. With the huge scale of flu every year, it would be hard to argue that those measures actually work.

Direct Relief: If coronavirus continues to spread into a pandemic on the level of SARS, what are the likely long-term economic and social impacts?

Shah: There’s going to be huge economic fallout from this. It’s only just starting. SARS had a huge economic impact, and that wasn’t nearly as widespread as this thing will probably be. China is clamping down on its trade routes and travel routes. How do you function in a global economy without China? We don’t know.

All of these outbreaks, when they go global, just show us again and again how interconnected we are, and how much we really rely on each other for all of our essential services.

Direct Relief: Why do you say it’s going to be bigger than SARS?

Shah: Well, because it’s only just starting. New outbreaks are being seeded right now. We know 5 million people left Wuhan before the travel restrictions were put into place, and that’s a lot of people.

Each of those people could seed new outbreaks if they are carrying the virus, and I think we’re seeing the first signs of that.

It appears to be carried by people who are non-symptomatic. That means it’s going to be really hard to contain it. I don’t think we’re anywhere near the peak or end of this thing. If it goes on on the current trajectory it’s going to be bigger than SARS.

[The virus is] not necessarily more deadly. It always seems more virulent at the beginning, because all you see are the worst cases. So as we get more information, it will probably become clear to us that it’s less virulent than we originally thought, but that doesn’t mean it can’t have a huge toll.

Because if something’s really catchy, even if it’s only slightly more deadly than a regular flu or respiratory illness that we’re used to, a lot of people can get sick and can die.

This interview has been edited and condensed.