The Nature of Epidemics

Why do epidemics end, and how is suffering and death minimized during an epidemic?

Please understand that I am not talking, here, about horrendous epidemics caused by pathogens that have been established to either have an extraordinarily high mortality rate or cause regrettable irreversible sequelae—like small-pox, polio, and measles. I am talking about epidemics of influenza-like respiratory illnesses—seasonal flu (caused by influenza A, influenza B, common coronaviruses, and other common respiratory viruses) and now COVID19. Granted, we are still learning about COVID, but data collected to date suggest that the threat posed by COVID is similar to that of seasonal flu viruses, as opposed to being similar to smallpox or polio.

Here is my understanding, for what it is worth:

Epidemics have a natural shape, including a natural ending. (See Graphs associated with Table A.) They start relatively slowly, then rapidly rise, then plateau, then subside. Ultimately, it is collective immunity that ends the epidemic. We will get back to this, but first let me hasten to emphasize that human responses during the epidemic are also hugely important.

Human efforts can greatly decrease the number of deaths and amount of suffering, particularly at the peak of the epidemic, and can spread out the epidemic so that it does not so rapidly overwhelm the health care system. In fact, that is what China did pretty well during the Hubei COVID epidemic, though they got off to a slow start in doing so. By hugely mobilizing physicians, nurses, ventilators, and medications from all over the country to help Wuhan, even heroically building a new hospital, they were able to take good care of the sick and prevent many deaths that would undoubtedly have occurred without such a heroic response.

But, the “lockdown” component of the response in China is mis-understood. A lockdown is extremely important at the level of the vulnerable, but a lockdown of the entire society is generally unnecessary and even unwise—for the kind of epidemics that are the subject of this essay. What needs to be locked down are the Nursing Homes and retirement complexes, as well as lockdown of the vulnerable who are scattered about. By the “scattered vulnerable,” I am talking about the elderly and the otherwise frail who are living scattered about. They need to go into a considerable degree of lockdown in their places of residence, for their own protection, while members of the healthy, young population kindly bring them food, and otherwise attend to them, being very careful not to bring virus to them. Group shelters, such as a designated converted hotel, could be made available for some of the scattered vulnerable.

While locking down life for the vulnerable (to maximally protect them), the rest of society (the far less vulnerable) need not be on lockdown. They need to maximally use disciplined common-sense preventative measures, but not more than that. And, on balance, it is acceptable if some of the non-vulnerable become ill, because, with very rare exception, they will not become life-threateningly ill, and if they do, it will likely be due to excessive immune reactions (e.g. cytokine storm) and it is known how to treat such reactions when/if they occur.

While the vulnerable are being protected (via selective lockdown) and the non-vulnerable are being careful but not in lockdown, a sufficient percentage of the non-vulnerable population becomes benignly (relatively speaking) infected and develops immunity—-and it is this wide-spread collective immunity that makes the epidemic die out, due to an eventual lack of available hosts for the virus. Better yet, all of those who do become benignly infected will have a measure of immunity that will help protect them (and, indirectly, others) during a future epidemic.

The important goal is to blunt the number of DEATHS and the number of new cases among the vulnerable, but not necessarily the number of new cases among the non-vulnerable.  In fact, the more cases of infection in the non-vulnerable, the quicker the development of adequate “collective immunity” and the more solidly the epidemic comes to a natural inevitable and definitive end—which occurs because there is no longer a sufficient pool of hosts available to sustain the viral invasion. At that point, the virus knocks on the doors of those who have developed immunity, they are welcomed in, and are promptly killed. An insufficient number of innocent, unarmed homes are left to sustain the viral invasion; too many homes are armed with antibody (or T-cell immunity) to allow the viral invasion of the community to continue. It is because of this “collective immunity” that the epidemic ends. Each member of the less-vulnerable population (young and healthy people) that becomes infected contributes to the collective immunity.

That is why a total lockdown (except in known extreme situations with rare pathogens, such as smallpox) is generally not wise. By trying to keep the community sterile, by trying to keep everyone from being infected, which is usually impossible anyway, too many homes would remain innocent, unarmed, unprotected. Those homes allow the viral invasion to continue, and to come back. There is not enough collective immunity to snuff out the invasion. Total lockdown messes with the natural process that normally protects us, as a group, during viral invasion. It messes with our collective immunity, which we depend upon not only to end a current invasion, but to prevent, or at least minimize, a future epidemic involving that or a similar virus.

So, it was not the “total lockdown” that brought the COVID19 epidemic in China to a close and saved China from what was feared to be “the deadliest virus we have seen in our life time.” It was collective immunity in Wuhan that ultimately ended the epidemic. And, in the meantime, heroic medical efforts and lockdown of the vulnerable, were responsible for markedly reducing deaths and suffering. The fact that the COVID19 epidemic in China claimed 3300 lives, as opposed to the 7-39 million deaths it was projected to cause, suggests that the better-than-expected outcome was not just due to collective immunity and heroic medical efforts, but greatly due to the virus being much less deadly and contagious than it was initially feared to be.

In India, where the epidemic has barely begun, the wisest strategy would seem to be to lockdown and protect the vulnerable and rapidly mobilize medical resources to all the places in need, but not lockdown the entirety of society. Leadership is needed to properly educate the public and mobilize the medical care effort; but authoritarian leadership, unthinking obedience, and harsh enforcement are not needed.  The people can easily understand what is needed of them, if it is properly explained to them, and the vast majority will be more than happy to do what will be most helpful. Authoritarianism, blind obedience, martial law enforcement, and fear in general—are not needed and should be avoided.

The same above plan could be used for seasonal flu, which annually kills between 12,000-61,000 people in the USA, most of whom are elderly and/or medically vulnerable. It is essentially a “Protect the Vulnerable (PTV)” plan. If we were to routinely implement a semblance of this plan (at least briefly) at the beginning of each year’s flu epidemic, and if we were to properly trat those who become ill, many of the tens of thousands of seasonal flu deaths that occur each year in the USA might be prevented.

An absolutely fundamental and essential component of managing an epidemic is proactive, prospective data collection, including massive large-scale testing/retesting of the population, starting as early as possible in the epidemic, especially in an epidemic of a novel pathogen. That is the way to most rapidly and maximally learn about, and adjust to, a current epidemic and learn how to better handle future epidemics. Many characteristics of an epidemic need to be determined—the mortality rate, the degree of communicability (R0), the mode of spread, the incubation period, the extent to which virus on inanimate surfaces remains infectious, the clinical characteristics of the illness, the spectrum of illness, the origin of the virus, the reason for appearance of the virus, the reason for the epidemic occurring where and when it does and to the extent to which it does. These characteristics must be determined scientifically, not just be based on initial assumptions that remain inadequately studied.

So, it is the magic of the immune system—the collective immune system—that ends an epidemic.  It is the magic of altruism, common sense, common decency, enlightened leadership, good science, good data, Public demystification, wide-spread shared clarity of thought, high spirit, careful distinction between assumption and truth, practiced compassion, critical thinking, thoughtful dialogue, collective effort, calm, discipline, hard work, attention to detail, and a superb health care system that minimize the death and suffering during an epidemic—while the collective immunity protects, both in the short term and long term.

In short, it is Human Goodness, Social Beauty and the synergy between the magic of the Human Spirit and the magic of the Human immune system that leads to the successful end of an epidemic.

Compared to the above, how has the USA responded to the COVID epidemic? It was appropriate to initially assume that the COVID virus might be extraordinarily communicable and extraordinarily deadly, and it was appropriate to initially exercise “an abundance of caution.” However, adequate testing was not implemented in a timely or competent fashion, and still has not been done. Adequate resources were not mobilized to health care facilities, all of which were already ill-prepared and overwhelmed before the COVID epidemic even arrived. Instead of learning from cumulative data collected in other countries (and in Washington state) and comparing those data to decades of experience with seasonal flu, initial assumptions have been maintained, unchanged, and portrayed as truths, despite data to the contrary. Based on those assumptions, 90% of the USA and half of Humanity have been placed on a considerable degree of “lockdown.” If some bioweapons lab had accidentally or purposefully unleashed a radioactive form of smallpox, the USA response to COVID would be appropriate. But, the data to date suggest that COVID is not more communicable or more deadly than seasonal flu and can be managed in the same way that seasonal flu is best managed.

There is no place for fear-mongering, lazy analysis, bad science, poor quality data, dogmatism, and portrayal of assumption as fact. There is no place for authoritarianism, blind obedience, shaming, finger-pointing, panic, martial law, rationing of care, disposal of dignity, and sacrifice of the elderly and frail.

And, there is no place for credit-seeking or misleading attribution of credit. Credit should be given where credit is due, but attribution of credit should be accurate, truthful, and based on good science—good medical, social, and political science—not on assumptions or hidden agendas.

RMR

3/30/20