In 1918, when the Spanish flu began spreading across the globe, ultimately killing at least 50 million people — making it the deadliest pandemic in modern history — many doctors and researchers were taken by surprise.
By that point, medical science had come a long way in discovering methods to understand, prevent, and cure spreadable diseases. Vaccinations were introduced in the West in 1796 by the English physician Edward Jenner and further improved by Louis Pasteur in the 1800s, and bacteriology was established as a research field in the 1880s.
As Mark Honigsbaum, the author of “The Pandemic Century: One Hundred Years of Panic, Hysteria, and Hubris,” puts it, the Spanish flu was a grim “rebuke” to all the medical advances that came before. “It was seen as a point where medicine failed,” he says. “It was caught, essentially, with its pants down.”
In his new book, Honigsbaum, a British medical historian, examines pandemics over the last hundred years, emphasizing that however far science has come, threats still loom large. Even now, he says, we’re living with the viral descendants of the H1N1 influenza virus, which caused the Spanish flu. The anti-vaxxer movement — fueled by propaganda on Facebook and YouTube — represents another danger.
For this installment of the Undark Five, I spoke by telephone with Honigsbaum about the origins of “vaccine hesitancy,” how poverty and social class intersect with public health, and how climate change is opening new doors to the spread of disease.
Our conversation has been edited for length and clarity.
Undark: We have seen great advances in technology and medicine over the last century, yet pandemics still pose a great threat. A report from the National Academy of Medicine states that the “underlying rate of emergence of infectious diseases appears to be increasing.” Why is this?
Mark Honigsbaum: The argument is that because of globalization and the way the world is becoming more interconnected, “the rules of viral traffic” have changed, according to virologist Stephen Morse. There are many more diseases that are emerging from animal reservoirs and ecological niches that used to be far removed from human populations. Because of the pressure of human populations and incursions, typically into rainforest-type areas — previously animal habitats — what seems to be changing is that wherever there are disruptions to public health systems or faster road and rail and traffic links, viruses can reach every part of the globe.
We can’t say we have more diseases, but we are more aware of these threats. We’re better at surveilling them. In becoming hyper-aware of certain threats, having a fixed medical notion of an infectious disease often blinds scientists and microbiologists to the unknown threat that is lurking in the shadows. When that comes along, it frequently takes the public health community by surprise.
UD: The spread of pandemics is influenced by social and environmental factors. How does social class and wealth intersect with disease? Are the poor more vulnerable to becoming infected?
MH: Let’s just talk about Ebola. When I was in Sierra Leone in 2015, I was struck by the fact that wealthy Sierra Leoneans were concerned, but their wealth was able to insulate them from the risks. Essentially, they were living in high-rises, not in rural communities where they were at a great risk of exposure. The other clear example is the health care workers in Sierra Leone. If you were a Sierra Leonean or a Liberian, you took your chances at an Ebola treatment center. Whereas if you were European, you would have been medevacked to a state-of-the-art facility.
In some cases, that doesn’t apply. Influenza is a classic example of a disease that, whether you’re rich or poor, it makes no difference. It’s a universal disease.
Of course, it does make a difference if you have a compromised immune system, you’re elderly, you’re pregnant, or you have an underlying condition, like asthma. Then it’s very important to be vaccinated. If you can’t get access to vaccines because you have to pay for them, then yes: having money or not having money will make a huge difference.
UD: “Vaccine hesitancy” is one of the World Health Organization’s top 10 public health threats of 2019. How has it come to pose such a great threat?
MH: I think it’s interesting that the WHO said that. Who could’ve anticipated that this wonderful medical technology — vaccination — which has saved more lives than almost any other technology in the history of medicine, except for possibly antibiotics or quinine against malaria, how is it that skepticism about this technology, and the way those ideas have been allowed to flourish on social media, is now, in itself, causing outbreaks of measles?
This is another example of the way that our understanding of infectious disease, and our attempt to control it through rational scientific means and technologies, is constantly being disrupted. It seems quite clear that, if you have enough groups [on social media] saying this, it has an effect on vaccine compliance. That’s why we’re seeing outbreaks that have the potential to become huge epidemics.
We’ve seen a huge rejection of expertise of all sorts. Just as Ed Murrow or CBS News no longer speaks for the nation, the CDC, or leading vaccine scientists, are no longer seen as gods. My wife is American, and her parents always said, “Doctor knows best.” But we’re no longer in that moment. There are all sorts of reasons why, but it’s very clear that there’s a huge distrust of elites and expertise in all its forms. There’s also Web 2.0, and the way it’s flattened the media environment, so we no longer have this vertical, top-down communication, where trusted legacy media filter out and select what’s fact from conspiracy theories.
What struck me about the anti-vaccine movement is that there are a lot of medically-trained people who have joined it, and some of the research is quite good. So I think something else is going on with vaccines — just as medical science has pushed back the frontiers of the unknown, there are still large areas of knowledge where we don’t know everything.
UD: Can you talk about how climate change can pose threats in terms of the spread of disease? What concerns you the most?
MH: The best example is Zika. Climate change particularly affects arthropods — insect-borne — diseases. If you have warming temperatures above 1,000 meters, the mosquitos can extend their range from the forest floor higher up mountain ranges.
Changing patterns of rainfall in these large megacities in Brazil and other parts of the world can also change the diversity and types of mosquitos that are able to breed in urban areas, versus just in forested areas. That means that arthropod-borne diseases like dengue, yellow fever, and Zika can not only appear in one season, but can return again and again.
We still don’t know exactly why it is that Zika broke out in Brazil, but we know it wouldn’t be possible without the reintroduction of the Aedes aegypti mosquito, which was pretty much eradicated from urban areas by the 1930s.
But also, Zika broke out in precisely those areas where people were living in large rundown areas without access to regular water. The combination of changing rainfall and warming and these social-environmental factors create a perfect storm.
Because global warming causes huge distress to human populations who may already be crowded together, and displaces people across borders, pathogens can be introduced to new communities that haven’t been exposed to them. And people may be forced to go deeper into forests to collect firewood, which means that their chances of coming into contact with unknown zoonotic infections increases. These are all ways that global warming can complicate patterns of disease transmission and emergence.
UD: You write that addressing these issues is “not a matter of knowledge, but of political will” — but the Trump administration is stripping funding for scientific research. What kind of impact will this have?
MH: It’s a devastating impact. You only have to contrast the way the previous U.S. administration responded to the outbreak in West Africa to the reluctance of the current administration to send any officials to the Democratic Republic of Congo [during the recent Ebola outbreak.] It’s only recently that the head of the CDC got on a plane to look at the situation.
It’s tempting to think: “We don’t need to bother about it; it’s over there, thousands of miles away.” But the lesson since SARS is: We can’t afford to ignore these problems. These diseases can get anywhere very rapidly. It’s in our self-interest to contain them before they get out of control.
And it’s going to be very much more expensive to wait, as we did [with Ebola] in 2014, until it becomes a huge disaster, and you have to send in military and humanitarian aid and mobilize huge resources in order to stop it from spreading outside West Africa.
At the moment, the Democratic Republic of Congo has this very stubborn, ongoing outbreak. What’s disturbing is that we now have a vaccine that seems to be pretty effective, and worked in a previous outbreak in the DRC — but because of the huge distrust of vaccines, there are a lot of people who are going under the radar and spreading Ebola. It is now officially the second-biggest outbreak of all time.
We’re seeing a new pattern emerging; it’s not clear what the pattern is, but it doesn’t look good. America has taken a huge step backwards.
Hope Reese is a writer and editor in Louisville, Kentucky. Her writing has appeared in Undark, The Atlantic, The Boston Globe, The Chicago Tribune, Playboy, Vox, and other publications.