(2021-09-02) ZviM Covid 9/02 Long Covid Analysis

Zvi Mowshowitz: Covid-19 9/02: Long Covid Analysis. The big Covid development this week was about Long Covid, as we got multiple analysis posts on the subject and some extra data as well. My conclusions on magnitude have not changed much, and I continue to believe that Long Covid is a thing worth some effort to avoid, but it is not as severe or common a thing as some reports would suggest, and that it is not a big enough issue that one should make big changes in life to avoid it, when you compare it to the effects of long-term Covid prevention.

Executive Summary
Quiet week.
Vaccines still work.
Case counts did not peak yet, but positive test rates likely have peaked.
Long Covid writeup from Scott Alexander.

The Numbers

I’m not convinced the number of actual Covid cases is still rising, but that is certainly possible with case counts rising. Schools are going to reopen soon, which may cause trends to change

Vaccinations

seem like it’s not going to be a big increase in the wake of full approval of the Pfizer vaccine.

I continue to be highly suspicious of all Israeli evidence that claims the vaccines fade quickly or aren’t that effective, because I’ve seen enough Israeli data that turned out to be the result of bad statistical practices

That said, there’s enough evidence that I’m willing to update. I now believe that natural immunity via previous infection is stronger than immunity from vaccination, plausibly much stronger. That doesn’t mean my estimates of vaccine effectiveness are moving down that much, it’s more that my estimates of immunity from previous infection are going up. At this point, personally, if I was confident I’d previously had Covid-19, I’d be treating myself as close enough to fully immune as to be entirely ignoring the pandemic on a personal level, beyond respecting the requests of those around me.

Vaccine Mandates

Spokesperson for the National Religious Broadcasters fired for statements supporting vaccination.

Mask and Testing and Other NPI Effectiveness and Mandates

A thread discussing new evidence on effectiveness of masks via interventions in villages in Bangladesh, a post linking to the source, and the full paper. Funding came from GiveWell, because the world is small. Data needs more analysis to translate it into good effectiveness numbers, as these situations get complicated quickly

yes this makes it clear that masks definitely do help somewhat, especially with proper (in this case surgical rather than cloth) masks, with the impact concentrated among the elderly.

It’s also worth noting that this week we have a new study that KN95/N95 masks offer superior filtration to surgical masks, which matches my priors, so the upper bound on effectiveness here is higher than what you’d find with surgical masks, especially given that cloth masks were much less effective.

This was a good study and I’m happy we have it, but I’m at a loss trying to translate these results into how much masks work in terms of a given exposure with any confidence whatsoever

In addition to mandating vaccinations, Duke also tests a lot, with interesting results (article):

Yet Duke is not alone. Amherst is barring its fully vaccinated students from trips into town other than to ‘conduct business’ and instituting endless testing and indoor double-mask mandates (news post).

Think of the Children

Long Covid

A post-length analysis of the threat of Long Covid from someone I trust to be a good thinker, concludes that the threat of Long Covid while not zero is not so large as to distinguish it from numerous similar background risks we take all the time with such matters

The main event here is that Scott Alexander has a ‘much more than you wanted to know’ post on Long Covid.

The first thing to note is that Scott views the related news stories as remarkably good

an important foundational point for Long Covid, which is that Long Covid is not one thing, it is many things, and it is important not to conflate them.

For all of these it’s important to note that it’s confirmed seropositives rather than all Covid cases

I’d go a bit further than Scott and basically say that I’d treat the breathing problems, issues with taste and smell, and the fatigue as Long Covid, and the other symptoms as presumed to be coincidental or as indirect consequences.

Scott also lists this big chart of symptoms, click on it to read in full, I’m going to highlight the mental health area

The control group numbers here are terrifying. This is a crisis. I mean, WTF? Again, it raises the question of what are the effects of Long Covid Prevention on mental health and general well-being, and suggests that they might be far more serious than Long Covid.

the respiratory section looks grim

Scott also points out that the rate of recovery from fatigue due to Covid contradicts the general data that fatigue basically never gets better.

He notes the disagreement with the first post I linked to, and tries to then do a Fermi calculation of the chance of getting Long Covid if one lived a normal life, and gets very wide bounds, somewhere between 1 in 150 and 1 in 25,000. I think we can safely throw out the upper part of his range, as I think a 10% chance of breakthrough symptomatic Covid within a year isn’t reasonable if you do a little math, and it’s starting at 25% which seems higher than the studies referenced above would suggest, so I think the range here would be more like 1 in 1,000 to 1 in 25,000.

I agree with Scott’s view here that our worries about Long Covid strongly imply the need for more worry about Long Disease in general, and also Long Everything. The previous Aceso Under Glass post emphasized this point, that there’s lots of such risks in the background all the time, and this isn’t an especially big one.

I haven’t yet done a full reading of the Matt Bell post that Scott references. It is long and I do not currently have the time. I hope to read it carefully over the coming week

Long Covid seems legitimate, and worth a nonzero amount of effort to minimize, but my model says it is mixing a lot of things together, is largely typical of what happens after being sick, is protected against by vaccines similarly to how they protect against symptomatic disease, and in many studies they go on a fishing expedition for symptoms then attribute everything that happens chronologically after Covid to Covid.

Thus, basically, ‘don’t do stupid stuff’ still applies, but I have no intention of going beyond that rule, or forming a microCovid budget or anything similar to it.

In Other News

Fluvoxamine preliminarily looks good (as in, worth using, see paper) as a treatment for Covid-19. Not good enough to change general behavior much while you’re healthy, and it’s got enough side effects that one wouldn’t want to use it lightly, but I’d be willing to take it if I knew I had symptomatic Covid.