Long covid is a post-viral syndrome that affects about ten percent of the people who catch covid. I'm just about a year out from getting covid due to a bad risk calculation, and am more-or-less fully recovered, but it took a long time, and I've got various lingering things that may be due to my age, which continues to increase daily, or may be unresolved residues of a systemic viral infection, which may be ongoing.
Ten percent is a middle-of-the-road level of post-viral syndrome incidence, which is a topic that the medical profession is only just barely starting to acknowledge. I've heard many physicians say in the past year things along the lines of, "We're taught that when symptoms resolve there is no more disease" and "We're taught that when we can't detect the virus there is no more disease."
Why they are taught this is a matter of some interest, as both of these claims are false.
Consider four of the most well-known post-viral syndromes.
First, in the acute phase, polio presents as a mild fever in about 5% of patients. The other 95% are asymptomatic. About 1 in 200 people who are infected by the virus suffer irreversible paralysis, of whom 5-10% die, mostly from asphyxiation.
Among people who recover from polio, around one third will develop post-polio syndrome, often thirty or forty years afterward.
Second, in the acute phase, HIV presents as a mild fever in some people and is asymptomatic in others. It generally then remains latent with no overt symptoms for years before its progressive damage to the person's immune system accumulates to the point that they can no longer fight off opportunistic infections or cancers, and they die. This happens in very nearly 100% of people infected, and unsurprisingly the virus has not evolved to be less pathogenic. Why would it?
Third, in the acute phase, Epstein-Barr virus presents as a mild fever, and in far less than 1% of cases causes multiple sclerosis to develop some years later.
Fourth, in the acute phase, chicken pox virus presents as a mild fever and rash in almost all cases. The virus--like all viruses, so far as we know--remains latent in the body, and decades later can produce shingles, which occurs in about one third of all people.
From even this short list we can conclude that a disease presenting in the acute phase as a mild fever gives us exactly zero information as to its consequences years or decades hence, and you would have to be ignorant of the entire history of viral medicine to suggest anything else, which apparently does not prevent some infectious disease, IPAC, and public health physicians from saying it. Or other things as well.
As recently as last week Anthony Fauci said in the New York Times: "And then we found something that was stunning. When you looked at the titer of the virus in infected and asymptomatic people, it was the same. What the hell is going on on here? That was a big surprise... When I saw those data, I said: This is different. We're dealing with a disease the likes of which we've never seen before." 95% of polio cases are asymptomatic.
There are many other cases of "long" diseases, which have been studied for decades. There is a paper by B. A. Bannister that was published in 1988 and contains a table of eleven chronic conditions--including arthritis--known to be caused by previous infection, either viral or bacterial. The list has not gotten any shorter since, but the degree of medical attention paid to such conditions has barely moved.
Physicians are not scientists, have in general negligible scientific training, and are selected and trained in a way that tends to weed out the scientific virtues of slow contemplation and random exploration. There are good reasons for this: most patients need treatment now based on the symptoms they are presenting, not a long ponder about the possible statistical regularities in a large population that might have some implications in a few decades.
This explains why post-viral syndromes have been neglected by the medical community for decades. If one were to deliberately develop a set of health problems designed to evade medical notice, they'd look a lot like post-viral syndromes. They would occur years or decades after an initial mild or asymptomatic presentation, they would be in most cases rare consequences of the initial infection, and the symptoms they presented would be complex and irregular, varying in both degree and kind.
It's notable that the HIV/AIDS connection was recognized relatively early on in no small part because very nearly everyone infected with HIV got AIDS, and practically no one else did. Furthermore this happened relatively rapidly, typically in years rather than decades. That's the kind of correlation that even physicians can see.
Looking at the past we can see things that are almost certainly cases of severe post-viral syndrome, such as the burst of "encephalitis lethargica" that is at least temporally correlated with the rise of the Spanish flu in the second decade of the 20th century:
The encephalitis lethargica, as the disease came to be known, threw its victims into a deep sleep-like, motionless state. Some were virtually transformed into living, breathing statues while in the middle of regular activities, such as working or eating lunch.
What followed was absolutely typical of non-scientists encountering a perplexing phenomenon: nothing.
"The precise cause of the encephalitis lethargica is still a mystery," according to the article quoted above, which is false. A far more accurate statement is found on the encephalitis.info site: "So far, the cause is unknown."
It's not that we don't know "the precise cause", it's that we don't know the cause at all. For all we know it could have been something in the water, or the air, some industrial process or chemical used during World War I.
This in a world where we can figure out that the Antarctic ice shelves entirely melted four million years ago based on an analysis of octopus DNA.
Researching viral causation is hard. Most of the interesting things are happening inside living organisms, and most of those organisms are humans. Host-pathogen interactions are highly host-specific, so in practical terms it's the humans who have to be the research subjects, and there are laws against taking them apart to see what's going on inside.
But if we can figure out stuff about ancient climate by looking at octopus DNA sequences, I'm going to dare to suggest that it might just be possible to figure out stuff about human host-pathogen interactions in relatively non-invasive, possibly indirect, ways, or at least ways that are more ethical than deliberately setting policies that you know will expose the majority of a province's children to a class three biohazard while lying to parents about it, which apparently is the kind of ethical violation public health physicians have no problem with.
One way of skirting ethical constraints, which I've used myself on occasion, is for patients to experiment on themselves, which is being done right now by the Remission Biome project with regard to ME/CFS:
Our aim is to recreate this [remission] event and make measurements of our biochemistry before, during, and after, in order to better understand any improvements in our health in response to antibiotics and other interventions.
This is a great example of quiet contemplation and random exploration. It may not produce anything interesting, but then again: maybe it will.
One thing we can say is that direct approaches to post-viral syndrome are unlikely to be fruitful, even in the unlikely event such direct approaches could be carried out ethically and legally. Indirect approaches should be where we focus our attention, which means physicians are almost certainly not going to find them, and specialists in the individual sciences of the human body are going to be challenged because this is a case where rigid reductionism becomes a problem, not because of anything inherently wrong with reductionism--it is, after all, the only human way to actually understand anything complex--but because the modes of our reductive view of the body may not be appropriate to the kind of sideways analysis the study of post-viral syndrome probably requires.
That is, we study the body as physiologists, as immunologists, as cell biologists, as geneticists, and so on, whereas "post-viral-syndromologists" may need a slice of each of these, but far less than the whole, to create a reductive (and therefore comprehensible) view of the body's long-term response to viral insult.
Reductionism depends on dividing the world up, but how we divide the world up is a matter of choice. We draw edges where they are convenient to our understanding of and interaction with the world, and nothing else. The world constrains where useful or interesting edges can be drawn, but does not determine them.
We come to post-viral syndrome with a reductive division of the subject matter that was useful and interesting for researchers in the twentieth century, which is now somewhat implausibly far behind us.
The solution to this is not to try to adopt some kind of unnatural "holistic" view that could only be taken by a being that is not human. Humans can keep three to five things in mind at once. Reductionism is our way of accommodating this reality while still understanding the world. "Holistic" approaches ignore this human reality and demand we do something that is impossible for us, and antithetical to our nature. Insisting on a "holistic" approach is like insisting a worker lift the whole pile of gravel in one go rather than reducing it to wheelbarrow loads with a shovel.
Instead, we should contemplate how we might produce a different kind of reductive division of the subject matter of human responses to viruses, maybe focused on evolutionary history, which is always in view in this kind of work, but not necessarily central.
Also, post-viral studies tend to focus on specific diseases and conditions, and that focus follows the particular, historically contingent, reductive path of medical research in its division of the world into states based on either symptomatic effects or causal agents. That is, we study symptom states, like "cardiovascular disease", on the one hand, or the result of particular agents, be they toxins or pathogens, on the other, even though their symptoms may be diverse, as is famously the case of syphilis, for example.
Neither of these reductive schemes is carved in stone, and "post-viral syndrome" considered as an entity could easily be made a subject of study, rather than "ME/CFS" or "shingles" or "long covid". After all, Aristotle, the father of biology himself, didn't study "birds" and "bats" and "moths"... he studied wings, and legs, and eyes, and so on, conveniently dividing animals into components for comparative anatomical analysis, rather than dividing populations into species for behavioural or other kinds of analysis. Where we draw the edges of our attention are up to us, based on our needs as knowing subjects, constrained by the objective nature of the world.
That's one suggestion. There are very likely others. Science thrives on diversity: Bayesian updating works best in a population where there are may different priors, so we can watch them all being updated and get a sense of where the system is headed, which is much more difficult with just one.
Post-viral syndrome is understudied because it falls into the cracks of the system of reductive understanding we have built medical science on. We need to find cross-cutting modes of reduction that will put it into focus, either with the kind of collaborative approach used so commonly in physics or as a field of study in its own right. Post-viral syndrome is a known and significant cause of human misery today, and it would be vile to simply shrug and say, "Well, people have always suffered from this, I don't see why we should bother doing anything about it now just because we understand so much better what a big deal it is."
We're better than that. Aren't we?
Post-Viral Syndrome
Well said, Tom 👍
Very clear analysis! Thank you.