Is Progress Possible? The Plague Cycle

It might seem counterintuitive to ask in the middle of the COVID-19 pandemic, but is humanity winning the fight against infectious disease? TPN Member and Senior Fellow at the Center for Global Development Charles Kenny says we are. But we must continue availing ourselves of the solutions that have led to this progress if that answer is to stay.

In this interview, Kenny speaks with TPN Executive Director Emma Varvaloucas about his new book, The Plague Cycle, outlining the immense headway humanity has already made in flattening “the plague cycle” and what we need to keep doing it, talks about the beneficial ripple effects of our triumph over infectious disease (think: women’s rights), and sets our current pandemic experiences in the context of history. Watch the entire conversation below or read an extract, which has been edited for brevity and clarity.

Emma Varvaloucas: I was looking at The Plague Cycle as a giant report card on how the world and, as you put it, humanity is doing versus infectious diseases. If we use that report card analogy, what are our grades looking like? Are we passing or failing?

Charles Kenny (CK): It’s a bit of a tough question. My high school used to give report card grades with two parts for each subject. The first part was how you’re doing on the tests. And the second part was how hard you’re trying. Even with COVID, even with the tragedy we’ve seen over the last year, you still have to give us a pretty good grade in the long historical sweep.

To take one example, if you look at the death rates of children—those under five worldwide—every five seconds or so, a child passes away. Now that is a tragedy, and a lot of those deaths are preventable. But if we had the death rates of just a few decades ago, it would be one child every second. We’ve made immense progress against premature death. COVID has knocked us back a few years, and it’s tragic, but it’s still a blip in historical terms compared to the victories we’ve made.

That said, COVID is also an example of a disease that we should have been able to beat back far faster with far fewer deaths. So I think we get a pretty low grade in terms of trying hard against COVID. The cover of The Plague Cycle is a beautiful piece of artwork that borrows from a picture of Death stalking Manchuria in the late 1800s, when there was an outbreak of pneumonic plague. It was a terrible airborne version of the bubonic plague that killed many millions in medieval Europe. The disease was fought back in Manchuria within a few months using social distancing and travel restrictions and all of the techniques that, 120 years later, we still didn’t manage to lock down with COVID. And I think it’s a sign. We’ve made all this immense progress. We’ve got these fantastic vaccines so fast. And yet, we really should have done so much better. And that has led to a tragic loss of life.

Another figure that stuck with me from the book was average life expectancy: something like a hundred years ago, the average life expectancy was 33. I read that and thought, “If I had been born a hundred years ago, I’d probably be dead in three years.” That was psychologically helpful for me. Even though we could have done so much better with COVID, we have still set ourselves up for success, and if we could follow through on that potential, we could do really well.

CK: Absolutely. The victories against premature death, I think, are humanity’s greatest victory. As you said, a hundred years or so ago, life expectancy was in the low- to mid-30s. And now, worldwide, the average is about 70. That’s largely because of victories against very young death in particular. And it’s changed the world in dramatically positive ways. The average parent 100 or 150 years ago would have expected one of their children to die at a young age—before the age of five, before the age of 10. That was just normal. That was the average. And now, thankfully, even in the poorest countries, most parents don’t go through the pain of burying a young child. I don’t think you can have any single measure of progress that’s better than that.

The long-term story is really positive and shows what we can accomplish, but it also points to how much further we’ve got to go. There are still hundreds of thousands of children dying each year from vaccine-preventable conditions, which are fairly simple things to fix. So we’ve got a long way to go, but we’ve come a long way, and I think that’s one of the reasons for thinking that we can get further.

What are the things that have brought us to this point? We know, as you just said, that there are simple fixes that somehow haven’t been done. What are those simple fixes and how can we make that final push?

CK: We need to vaccinate using the vaccines we already have. COVID is showing us that now; it’s incredible that we might be throwing away COVID vaccines because we aren’t using them fast enough. But this is part of a longer-term story of not vaccinating everybody against the diseases for which we already have vaccinations.

We also need vaccinations that we don’t have. Most important, perhaps, we need vaccines for the mass global killer of malaria. We are seeing progress on that. And I think maybe in the next few years we will see a malaria vaccine, and that will be fantastic news, especially for tropical parts of the planet.

I have hope for new vaccines. But there’s also a bunch of old stuff—stuff we’ve known about for 100 years. There is better sanitation: making sure everybody has a decent place to go to the toilet really helps. It massively reduces the spread of disease. There’s making sure everybody has easy access to clean water. There are basic public health measures that we still need to make sure the world as a whole has access to. And if we achieved all of that, we would be going a lot further and making a lot more progress, and there would be much lower child and adult mortality worldwide.

The simple power of having clean toilets and washing your hands: it’s easy to forget these things are not a given for a lot of people and weren’t a given for most of human history.

CK: One of the things I talk about in the book a bit is—and apologies to believers out there—Christianity in its early stages was a really dirty religion. In ancient Rome, Christians went around saying that young women should never be naked. They should be ashamed to be naked, so they should never take baths.

For a lot of history, we were pushing back against the things that improve human health. And one of the great things about the last 100 years or so is that we figured out the germ theory of disease. We figured out how infection spreads. And that knowledge is a massively powerful tool in reducing the burden of disease.

Right, and again, it’s easy to forget this stuff. You talk in the book about the miasma theory that infection was spread through bad odors in the air. It’s such a boon to know exactly how COVID is spread. We knew exactly what to do, even if we didn’t do it perfectly, or even well.

CK: One example I mention in the book is John Snow, who was a London anesthesiologist who realized during a cholera outbreak that a lot of the cholera cases were connected to a single pump that people were using to collect water. He theorized that whatever was causing the cholera was coming in through the water, and he was right. Then he took his theory with a lot of evidence—maps of where the deaths were and who was drinking from which pump— to Parliament. The members of Parliament in London turned around and scoffed at him and said, “Oh, come on. We all know that cholera is caused by bad smells, not by little particles in the water. Don’t be so ridiculous.” And they ignored him.

The lucky thing was that, in London at the time, the sewage system emptied into the Thames. Parliament is right by the Thames. It’s a beautiful Westminster building right on the Thames, and the smell from all the sewage worried parliamentarians that they were going to get sick. So they financed a much better sewage system because they believed in the miasma theory, because they were worried about the smell. As it happened, the sewage system took all of the sewage way downstream. And that meant the water that the Londoners were taking out of the towns stopped having cholera in it. But it was by accident. It was this belief in a completely incorrect theory that luckily paid off. But now we’re in a much better position to know how to fix problems and how to do it well, because we have a much greater understanding of what’s going on.