The past is never dead. It’s not even past,” wrote William Faulkner. I think of this line as I continue to study the last great influenza pandemic to devastate the world, foreshadowing 102 years ago, the devastation of our current pestilence, COVID-19. Yes, as my medically trained friends point out, one cannot take the similarities too far. The Coronavirus is a different genre of virus, originating in bats (a mammal) while the H1N1 virus that carried the 1918 influenza came from avian genes, though it might have transited through swine. COVID-19 kills differently and more directly than the H1N1 virus. And unlike the H1N1 virus, which mutated from a mild and very brief infection to a very virulent, deadly one in its second wave, so far at least, the Coronavirus has not mutated fundamentally, although the nature of the expected second wave is yet to be seen. There are certainly other, more technical, differences not apparent to a layman like me.
But from the historical perspective, there are similarities that also stand out, and from which we can learn, while we also develop our ultimate weapon: a vaccine to defend definitively against the virus. Both viruses leaped from animals to humans and were completely new to humankind which had no natural defense to them. Both spread rapidly through the human population. And in both pandemics, scientists searched, or are searching, frantically for a vaccine or drug cure — never found in 1918/19; yet to find in 2020/21.
And both have cosmic impact that is/was/will be transformational in one way or another. The most important similarity, however, is that lacking a pharmaceutical defense — a drug or vaccine – in both cases so far, societies a hundred years apart have taken identical defensive non-pharmaceutical interventions (NPIs) to mitigate the immediate impact of the viruses, and to try to save lives. The 1918/19 virus slowly lost its power to spread, though it returned in lethal but much more limited waves in the following couple of years, and then just disappeared. I have seen no explanation of why or how.
There remains the question of why these two particular pandemics have been so qualitatively different than the many other pandemics that have come along in the years between. These lesser pandemics come and go every decade or so and kill a lot of people that wouldn’t have died otherwise, but are so limited in their impact on the society and the economy that they are forgotten, not by the scientists, particularly the epidemiologists and the medical profession in general, but certainly by the general public. How many of us remember the Asian Flu Pandemic of 1957, spread by a H2N2 influenza virus, which killed 70,000 Americans and a million worldwide? I am probably one of the few non-scientists who remembers, but only because it sickened me for three exceedingly difficult weeks when I was a second – or third-year student at university. And I was very sick, but not sick enough to be admitted to the university hospital which had all its beds already full of fellow students. And yet, I just checked with one of my closest friends at the university, who lived in the same dorm, but he did not get sick and has no memory of the pandemic and its assault on the Stanford student body. There have been many other pandemics in the past 50 years, the 1968 second pandemic spread by another H2N2 virus, that I don’t remember, and the many since, too numerous to mention here, but none epic enough to make us fear for the foundations of our societies.
But the Coronavirus pandemic appears to have the epic, transformational power of the 1918 pandemic, and there is much concern about whether its severe economic impact will forever transform our economies and our social structures. And that is why studies of the 1918 pandemic are important. This article is intended not to meditate about pandemics in general but to follow up on the article I wrote two weeks ago, which described the tentative results of examinations of the efficacy of the NPIs designed to flatten the infection curve of that pandemic and thereby save lives. The principal conclusion of these studies was that these NPIs—school closings, prohibition of public gatherings, and quarantine/isolation (what we call social distancing)—did indeed flatten the curve of infections, and very significantly if done early and comprehensively enough, but were not in place long enough to affect materially the death rate. This article follows up on that by describing other recent scholarly examinations of the relationship between these same NPI mitigating actions, which most countries have in 2020 more or less copied to slow the spread of COVID-19, and economic recovery that followed the disappearance of the 1918 virus.
The primary source of what follows is a paper, authored by Sergio Correa, an economist with the Federal Reserve Board, Steven Luck, an economist with The Federal Reserve bank of New York, and Emil Verner, an assistant professor of economics at MIT, entitled “Pandemics Depress the Economy, Public Health Interventions Do Not: Evidence From the 1918 Flu.” The title pretty much sums up their findings: to quote from an MIT News report on the paper, “taking care of public health first is precisely what generated a stronger rebound later…[US] cities that acted more emphatically to limit social and civic interactions had more economic growth following the period of restrictions.”
In the US at least, and I think in many other countries that also see their economies plunging into recession with unemployment levels skyrocketing, there is a raging debate whether and how to slow the economic bleeding and much motivation to dilute the efforts to mitigate the spread of the virus and to “reopen” the economy by allowing businesses and retail stores to reopen, people to gather in restaurants and bars, and so forth. Many of the US states that are taking this route have set guidelines and limits on business operations and public gatherings, but whether these will be followed and work to limit the spread of the disease is problematic.
Such decisions are really up to the states (though in previous cases the federal government has taken a strong leadership role—which it has not in this pandemic), and many states have started to reopen while their infection and death rates are still rising. Other states, mostly our largest in which the virus has already hit very hard (e.g. California and New York) are taking a much more cautious approach and planning a very measured and constrained path to reopening. But given the fact that state boundaries cannot be closed to each other, it is not clear whether the infection in states in which it rebounds after they reopen can still spread to those states trying to reopen very cautiously so as not to reignite the pandemic.
The authors of the paper generalise as follows: during the 1918 pandemic “the more exposed areas experience[d] a sharp and persistent decline in economic activity.” Manufacturing output fell by 18 percent, driven by both supply and demand factors. “Cities that intervened earlier and more aggressively [did] not perform worse, and if anything, [grew] faster after the pandemic [was] over.” In summary, their findings were that NPIs not only lower[ed] mortality, “they may also mitigate the adverse economic consequences of a pandemic.” In looking at data from 43 US cities, they found significantly different economic outcomes which varied according to their different NPI intervention. The best economic performers between 1919 and 1923 were the cities which “enforced above average duration and intensity of [NPIs] when the pandemic struck in the Fall of 1918, and that those cities that “instituted [NPIs] significantly fewer days” struggled economically afterward.
I doubt these findings will change the course of events in the next few weeks/months, and I expect that many other countries and many of our states will push on to “reopen” as their economies continue to tank and unemployment becomes a larger political problem, especially in an election year. In addition to politics, the so-called ”animal spirits” of people eager to return to work and to habitual activity will push people out of their social distancing mode. But the trade-off between public health interventions and economic activity so commonly referred to now in the debate on whether to reopen or not may be, in the analysis these authors, a false trade-off. Healthy economic activity may be dependent on good public health.