Unknown Long Term Consequences

 I want to make a point about the topic everyone's worried about, but I don't want to unnecessarily freak anyone out. As in, if you've already gotten it and have suffered no lingering effects, you should probably not worry. But if you haven't gotten it yet, you might want to exercise additional caution due to the unknown long-term sequelae. Some have persisting complications, but most people appear to recover in fairly short order. Those appearances may be deceiving. There is simply no way to rule out severe long-term complications, because the long term hasn't arrived yet. The data needed to settle the question only exists in the future. 

I'm sure some of you see what I'm doing here. Re-read the above paragraph, but do a little Necker cube flip and pretend I'm talking about the vaccine instead of the virus (or vice versa if you read it the other way). I'm tuned in to media sources that are hyper-cautious about either the virus or the vaccine (yes, I consume media on both ends of the spectrum), often making this "unknown unknown" kind of argument. What surprises me is the symmetry. Evidence of harmful side-effects of the vaccine are pretty weak. Some people are making a big fuss about the VAERS (Vaccine Adverse Event Reporting System) dataset, which the CDC uses to collect information on adverse reactions to vaccines. Below is a screenshot. You can tell from the file sizes alone that there's something odd going on in 2021. We're getting an outsized number of reports, apparently due to the mass vaccination campaign.

Certainly someone should be looking into this. It's concerning, but it's easy to dismiss. In fact, I urge that we dismiss it by default until someone convinces us there's a real underlying signal in this noise. There are so many more people getting vaccines this year, and the age profile of those getting vaccinated skews older than what we've seen in typical years. There are simply far more opportunities for adverse health events to happen to someone who's recently gotten the poke (I should say, "to happen to happen to someone"), compared to previous years. This is naturally going to yield some spurious reports of vaccine reactions. I haven't done the analysis to say that this year's explosion in adverse vaccine events is plausibly attributable to spurious connections, but I think that it's safe to ignore this until a more thorough analysis suggests it's compelling. In other words, just as I don't think we should jump at every shadow, I don't think we should overreact to signals that are probably spurious.* We  should have some mechanism for dismissing such false alarms, not indulging costly counter-measures just because "they might be real."

That said, even if the "evidence" is convincingly explained away as noise, there will be people who cling to this "unknown unknown" alarmism. You technically can't disprove that there are unknown long term health effects. Even if negative outcomes don't manifest in the short term, they could show up later in life (say as a subtle but real increase in cancer or infertility or something). I think this is nuts. It's a Pascal's Mugging approach to risk management. "A problem exists because I claim it exists...oops it probably doesn't but let's entertain the very small risk that it does because it would be very bad if it does." Followed scrupulously, this leads us to spending all of the world's resources on mitigation for risks that aren't real. Let's have a real budget for mitigating tail risks, but let's keep that budget finite.

I would make the same argument for "long covid." When I first started hearing reports of long covid, they sounded like a vague smattering of very different symptoms that people can suffer from from a variety of reasons.** Brain fog (which I have often felt this past year and a half, but which I attribute to a dramatic change in my work environment and lifestyle). Lethargy (which I didn't experience, but which could likewise be caused by being home all day instead of going to the office...perhaps metabolic disorders from changes in physical activity and diet). Abnormal heart scans (which it turns out will show up in similar proportions in a random sample of people...that OSU study didn't even have a control group!). It reminded me of the observation that a doctor can look at an MRI for a back pain sufferer and attribute the pain to some abnormality (like a bulging disk), even though that abnormality is common in the healthy population not suffering any back problems. My reaction was to entertain the possibility, but to basically dismiss it as having any decision-weight. And I think that was the right call. (Here is a good piece on the topic by Adam Gaffney, which I riffed on here.) To be clear, there are people who have severe bouts of covid, who perhaps end up hospitalized, who survive but have some kind of permanent lingering effects from it. I've never doubted or denied that. But from early on I was calling bullshit on the notion that mild or asymptomatic infections were leading to serious long-term health problem. I'm not buying this "silent killer" view of long covid, that there is a huge amount of harm that's slipping under the radar, but poised to strike in the coming years and decades.***

Of course, someone could concede all the stuff from the Adam Gaffney piece. "Sure, most of those 'long haulers' didn't actually contract covid. Sure, there's a spurious signal, and a million ways to confuse noise for signal, so we should have been more cautious in raising the alarm. But...the long-term consequences are unknown! The long term isn't here yet!" 

Vaccine alarmists and long covid alarmists can both point to "evidence for" the thing they're worried about, and both can take refuge in this all-trumping appeal to unknown risks. I just want to point out the symmetry. I think the "long covid" alarmists are on slightly more solid ground in terms of the strength of their evidence. But the appeal to unknowable hazards is not dependent on and does not respond to evidence. 

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*Someone surely has a deep knowledge of the rates at which people experience adverse health events. It shouldn't be too hard to check the rates at which we're seeing adverse health events in the VAERS data. Who knows, maybe it's actually ten times as common as we'd expect. I heard someone give the anecdote of a man having a heart attack moments after getting his first shot of the covid vaccine. I'm sure that seems salient if it happens to you. But I'm just thinking, "Old people are having heart attacks all the time. Surely someone was going to have one in near proximity to getting their covid vaccine, and surely some alarmist is collecting these stories and broadcasting them."

**I feel a need to cite Scott Alexander's excellent recent piece on long covid. I think covid hawks could use his analysis to say, "See! Long covid is real!" And covid doves could use his analysis to say, "See! Long covid is way overblown! (Yes it's real, but that's not the point of contention.)" I think the long covid hawks are committing a logical fallacy that's a common advocacy technique: give a high-sounding number by using an inclusive definition that captures non-severe examples, then cite specific examples of the most severe cases. This is a way of insinuating that severe problems are more common than they really are. Alexander is overall more concerned about long covid than I am, but I want to applaud the very high quality of his approach. See this part commenting on a study of a large number of post-covid symptoms: "One flaw in this analysis is that it didn’t ask for premorbid functioning, so you can tell a story where unhealthy people are more likely to get COVID than healthy ones (maybe they’re stuck in crowded care homes? Maybe they put less effort into staying healthy in general?) But I don’t think this story is true - how come obviously plausibly COVID linked things (like smell problems) are significant, and obviously-not-COVID-linked things like diarrhea aren’t?" Emphasis mine. Also here: "An English team says there’s a Long COVID rate of 4.6% in kids. But there was a 1.7% rate of similar symptoms in the control group of kids who didn’t have COVID, so I think it would be fair to subtract that and end up with 2.9%. And even though the study started with 5000 children, so few of them got COVID, and so few of those got long COVID, that the 2.9% turns out to be about five kids. I don’t really want to update too much based on five kids, especially given the risk of recall bias..." Section 9, about post-viral symptoms for other common viruses, was particularly interesting. As in, "How common are mild carry-over syndromes in general?" Maybe these are just as common for typical cold and flu viruses, but we just don't notice them because they're less prevalent in normal times? Or we're inured to them because, like the viruses themselves, we've accepted them as part of the background risk of a normal life? We don't happen to associate them with a recent cold or flu because it doesn't occur to us that it might be the cause? 

***We've seen population level increases in death rates. What I haven't seen are population-level morbidity figures. I'd expect to see disease rates increasing for the population as a whole, with dramatic increases for younger populations. And the analysis should clearly separate out the effects of acute covid from long covid. The population-level spikes in mortality are noticeable. If long covid is real, and if it's as big a deal as some are claiming, the population-level spikes in morbidity should be out of this world.