Long COVID: Slow Disaster-In-The-Making?


Image by Miguel Á. Padriñán from Pixabay

As COVID has raged around the world, the similarities and differences between COVID and its respiratory fellow-traveler Influenza have been much discussed. Comparisons with another viral epidemic—Polio—have been barely heard, but perhaps should be, because Long COVID may cause serious long-term health problems much as Polio did, and possibly on a much larger scale.

Like Polio, Long COVID may have significant impact on children, despite their low odds of serious harm from an initial infection. Nearly all of the focus to date on COVID’s impacts has been about hospitalizations and deaths. We have assumed that if we can prevent those two outcomes, we’re past the worst of the crisis. But long COVID might be the third bad outcome, emerging from the shadows.

Comparing COVID to Polio

Polio has been nearly eradicated today, but from the late 19th to the mid-20th Century Polio caused periodic epidemics in the developed world. Polio epidemics peaked in the United States in 1952, when 3,145 died and 21,269 were left with some degree of paralysis. We now know that, among children, about 70% of polio cases were asymptomatic, another 29% caused mild and temporary symptoms, and only about 1% resulted in paralysis or death. The mandated use of the Salk and Sabin vaccines brought the polio epidemics to an end in the US, and subsequent vaccination campaigns have made it possible to drive polio to the brink of extinction globally.

This 1963 poster featured CDC’s national symbol of public health, the “Wellbee”, encouraging the public to receive an oral polio vaccine.

The onset of paralytic Polio cases was quick and obvious: within days of infection, victims lost the use of some or many muscles, a very dramatic and visible symptom: they couldn’t walk, or couldn’t breathe, or couldn’t even stay alive.  Long COVID, by contrast, presents over 200 symptoms affecting ten organ systems, according to the UK’s National Health Service.

Many of these symptoms resemble the symptoms of other afflictions, they are highly variable in severity and duration, and they emerge over a period of time. A person can have an entirely asymptomatic initial case of COVID, yet still develop PASC (Post-Acute Sequelae of SARS CoV-2, a formal name for Long COVID). In many cases, the connection between an initial COVID infection and the emergence of symptoms weeks or even months later may not be immediately obvious.

For all these reasons, PASC is hard to diagnose compared to Polio. There’s no single test for it, and no cure. There are millions of cases of PASC in the US today, yet little public attention is focused on it. Were it not for the 635,000 deaths (and counting), the big story of COVID in America might be the story of so many people recovering very slowly, or perhaps not at all.

Many cases of PASC appear to resolve within weeks, or a few months at most–as is also the case for the slow-to-dissipate after-effects of other serious respiratory infections. It’s the lingering remainder which earn the comparison with Polio. Cases that don’t resolve within a few months may last for years; with a new virus, there’s no way to be sure, though some of the effects resemble long-lived afflictions such as Chronic Fatigue Syndrome.

It was very obvious that Polio’s consequences could last for a lifetime: children who were paralyzed in their youth could be seen coping with the continuing effects as adults. FDR’s Polio, contracted just a century ago in August 1921, left him wheelchair-bound until he died in 1945. It’s not yet clear what percentage of PASC cases will be of very long duration, since the virus itself, unlike Polio, is new. What is clear—and sobering—is that the worst effects of PASC are, if anything, worse than Polio’s, though not always as visible. I’m sure that if FDR had been asked to choose between having a permanently impaired ability to walk and a permanently impaired ability to think, he would have chosen the former.

How Bad Could It Get?

If PASC turns out to be a long-running serious health impairment for even 1% of those who contract COVID, the impact on our national health will be far greater than Polio’s, because COVID is so much more infectious. The stakes have been raised by the many Americans who have refused vaccines, masks, distancing, and other protective measures while the highly transmissive Delta variant has quickly become dominant, even though half the country—including nearly 90% of our children—remains unprotected by vaccination. Throw in the reopening of schools, and the table is set for a scaled-up stealth successor to the Polio epidemic.

PASC Symptoms and Causes

The most serious effects of PASC fall into three categories, according to researchers at the US’s National Institutes of Health (NIH):

  1. Exercise Intolerance: if you climb a flight of stairs, you could spend a day in bed to recover. You’ll spend many waking hours feeling profoundly fatigued and short of breath.
  2. Dysautonomia: your heart races, your blood pressure plummets, you get dizzy and risk falling down or driving off the road. You could spend a lot of time lying down to minimize risk, even in business and social settings.
  3. Brain Fog: you can’t remember the names of objects or people. You can’t keep track of time. You are subject to abrupt mood swings. Depression is common.

Other impairments include joint and muscle pain, loss of the senses of taste and smell, organ damage, disruption of menstrual cycles and—the ultimate infirmity for men—erectile dysfunction. This latter effect, if better publicized, could solve the male vaccination resistance problem overnight.

The causes of PASC are not known, though furiously sought. The main theories to date include:

  • The virus may survive in sanctuaries within the body.
  • The immune system may have been reset to attack the body itself.
  • One or more organs may have been damaged.
  • The thin layer between the vascular system and the organs may have been damaged.
  • COVID infections may trigger destructive behavior by other viruses which are long-term residents of the body.
  • The lining of the gut may have been damaged enough to let bacteria escape.
  • The clotting system may have been altered.

This is not a comprehensive list, and PASC may be caused by a mix of several causes, and the mix may differ from one person to the next.

A Catastrophe?

The most important question about PASC is the hardest to answer: how many cases may cause significant impairment which lasts beyond a few months, possibly for years or a lifetime? This question can’t be addressed yet with precision, but it is possible, based on what is known, to make some educated guesses, and it’s worth doing so, because such guesses could at least inform COVID policies adopted by governments, businesses, and, of particular importance, schools. Here’s some back-of-the-envelope calculations of how much risk faces us. Remember this is sketchy arithmetic—we’re trying to roughly assess risk rather than establish a precise number.

The United Kingdom’s Office for National Statistics (ONS) draws on the UK’s much higher rate of COVID testing (about 6 times greater than in the US) and longitudinal survey research to generate data about COVID (and much else under the sun, frankly). ONS has estimates for PASC prevalence in the UK that have no equivalent in the US, so I’ve used their data as a starting point, and then taken into account the differences in size between the UK and the US.

The US has about 5.85 times as many confirmed COVID cases as the UK so far. Taking the ONS number for people who report experiencing PASC symptoms which are still seriously impacting their lives 12 weeks or more after infection and multiplying by 5.85, I estimate that the US might have 930,000 people characterized the same way: serious effects, still impacted at 12 weeks and counting.  This is about 20% of all people currently reporting PASC symptoms of any kind and amounts to about 2.5% of all confirmed COVID cases.

Studies in the US of people with long-running PASC show than many (over half in some cases) who believe they had COVID and are experiencing symptoms have not had a positive antigen or antibody test along the way to confirm the original disease. How much of this is due to imperfect testing, lack of testing, some unknown way in which PASC might suppress antibody or antigen test positivity, or some kind of psychosomatic effect (believing it makes it real) is impossible to say. This is a reminder of how fluid these numbers are.

The 930,000 includes children, who are probably undercounted, since they aren’t very reliably sampled as self-reporters. I’ve seen estimates that children who get COVID develop PASC at one-fifth to one-third the rate of adults. There’s not a lot of good data out there yet about pediatric PASC, but if we take the overall rate of 2.5 percent and remove kids, we might arrive at an adults-only rate of three percent. A third of that gives us one percent of kids who get confirmed COVID ending up with seriously impairing symptoms lasting a minimum of 12 weeks.

This is lower than most estimates based on smaller studies, so it is perhaps conservative. The American Academy of Pediatrics reports 4.2 million confirmed cases of COVID among children (pre-Delta), which suggests that there might be 42,000 kids in America today with serious, long-running PASC. Note that confirmed COVID cases among children are thought to be seriously undercounted, so this number is also probably conservative.

Almost ninety percent of the 82 million Americans under 20 are unvaccinated, including the 55 million in K-12 schools. If 50 million of this young cohort catch COVID, that could lead to 500,000 cases with serious long-term impairments, and it could sneak up on us while we argue about mandates and desperately try to stave off having to return schools to remote learning again.

The 500,000 could well be very high (or even low), but three times 42,000 would be a plausible minimum, giving us a range of 126,000 to 500,000 impaired kids by the end of the coming school year. Remember, this is just kids. If Delta continues to rampage, the number of adult cases would also grow significantly, and we could have 2 or 3 million people with long-term impairments by early-mid 2022.

These numbers are not at all precise and could be very significantly wrong in either direction. The point is that they are plausible, and it would be almost impossible to make a strong case that the true number must be vastly lower. Compare this scenario to Polio, where about one percent of those infected by a much less contagious disease developed paralysis or died, resulting in 24,000 cases in its worst year. Those cases were impossible not to see. These COVID cases, in contrast, are easy to overlook.

As COVID evolves, eventually, into an endemic pathogen, the creation of new PASC cases will continue at a lower level–perhaps very low if nearly everyone eventually has some degree of immunity. If some percentage of each year’s cohort of new PASC cases is permanent or at least long-running, the total number of people living with PASC, with all the attendant impacts, will continue to creep upward until either cures are discovered and applied, new cases of COVID are almost entirely prevented, or the PASC population dies at the same rate as new cases occur.

What to do?

PASC is hiding in plain sight. It’s hard to see because it takes so many shapes and smears across time. The first challenge is to persuade decision-makers to focus on it—to see it—and begin to make decisions that take it into proper account.

Begin with scientists

Researchers into PASC are operating on the margins, doing small studies, and communicating findings swathed in layers of uncertainty. There does not seem to be much priority given to funding a steep learning curve about this threat, but there should be. All the focus is on stopping hospitalizations and deaths, which are driven by very serious cases of COVID,a dn which are exponentially more dangerous to our oldest citizens. PASC is driven instead by all cases of COVID, and is only modestly more likely to be found among older people.

Given how big a problem PASC might become, we desperately need better data about it. For example, how likely is PASC after a breakthrough case of COVID in a vaccinated person? This could be a great project for the Gates Foundation, which did some stellar early work on COVID vaccine development and has a deep interest in infectious diseases.

Make it a healthcare issue

There is at present no cure and not even much treatment for PASC. Researchers have suggested that PASC could, eventually, lead to dementia, heart disease, stroke, and even cancer as well as the impairments it directly inflicts on sufferers. There is unlikely to be a magic bullet pharmaceutical solution to PASC, so incremental treatments and rehabilitation will be necessary.

Make it an education issue

In recent research for another Post Alley story, I learned that PASC is not at all on the radar of school district administrators, the state Department of Health, teachers’ unions, or very many parents. K-12 students, however, are a large share of the remaining unvaccinated population, and, because they are young, permanent cases would potentially impact many decades of their as-yet-unlived lives. Schools turned out not to be hotbeds of infection last year, but Delta has changed the rules, and the schools this year could be at greater risk of COVID bonfires, and therefore PASC bonfires.

Make it an employer issue

If PASC indeed leaves millions of people with long-term health difficulties, it will burden the health insurance costs businesses carry and make a tight labor market tighter. Employers have every incentive to recognize that preventing infections in order to reduce PASC should be a business priority.

Make it an insurance issue

PASC is an insurer’s nightmare. If it is widespread, they can’t avoid it and they will hate to be on the hook open-endedly for an endless affliction. PASC could end up driving the US more completely into a national healthcare system.

Make it a pharmaceutical issue

Taking PASC into proper account could influence vaccine development strategy and give the vaccine makers incentives to develop updated vaccines and to market the vaccines in new ways.

Make it a community issue.

The best strategy for limiting PASC is extremely high levels of vaccination, in the US and in the whole world. This means overcoming the very locked-in opposition to vaccination which plagues the US. Part of the solution to this is going to be personal communication within families and between neighbors.

Make it a government issue

Vaccine mandates, research dollars, and programs to accelerate better ventilation all need government at one level or another. The FDA should be encouraged (to put it mildly) to give greater weight to the harm done by moving too slowly on vaccine approvals. To influence government of course, make it a political issue, starting now. What’s PASC is prologue.

Tom Corddry
Tom Corddry
Tom is a writer and aspiring flâneur who today provides creative services to mostly technology-centered clients. He led the Encarta team at Microsoft and, long ago, put KZAM radio on the air.


  1. Heard a doctor/researcher on NPR discuss post-Covid, Google her numbers, Googled some more, came up with at least 1,650,000,000 people world wide that will have post-covid/PASC – but could be far higher. And she feels none will recover automatically, almost all will die early, and many will be permanently disabled.
    She was in the micro-clot school, but said no one knows yet wat the cause really is, so there is no good test….
    Only way i can think of to deal with post-covid is to disarm world wide and put the money into health research and care…….


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