There wasn’t much discussion of long COVID here. At what risk of long Covid (including possibly chronic fatigue and brain fog lasting >6 months, up to the end of study periods, and possibly much longer) would you change your mind about this? I suppose it would still depend on your personal preferences, and how much you get out of certain activities (enjoyment and mental and physical health).
In my specific case (in Canada), I’ve decided to move out of my current dorm-style residence, since although it’s pretty empty now, I would have been sharing a kitchen with 17 other people (although I’ve been told less than half of residents ever really use the kitchen), and a bathroom with 3 other people. I’d also expect there to be parties with outsiders here, too. I think it’s likely that almost everyone would be vaccinated, though.
I think the evidence is somewhat ambiguous on long COVID rates at this point, even among the studies with actual comparisons/controls. A few of the higher quality studies with comparisons/controls were discussed here:
I’d somewhat lean towards lower risk estimates, since I think higher ones are more likely to be biased due to poorly matched controls, selection bias or unrepresentative samples. On the higher end of studies with controls, one of them (of healthcare workers) had small/insignificant differences in mental health between positive and negative cases, but (most worrying to me)
Neurological symptoms of statistical significance included problems sleeping through the night (60.7% vs 51.5%), forgetfulness (35.0% vs 19.0%), confusion/brain fog/trouble focussing attention (20.7% 27.9% vs 14.7%), trouble trying to form words (15.7% vs 9.2%), short-term memory loss (20.7% vs 5.6%) and, less frequently, difficulty swallowing (6.4% vs 2.4%), twitching of fingers and toes (5.7% vs 2.4%) and trembling (5.7% vs 1.7%). Respiratory symptoms of interest included unusual fatigue/tiredness after exertion (39.3% vs 17.5%), breathlessness after minimal exertion (25.7% vs 10.2%), chest tightness/pain (18.6% vs 8.2%), fits of coughing (13.6% vs 6.5%) and breathlessness at rest (9.3% vs 2.8%).
See Table 2. Positive cases were more likely to be patient-facing frontline clinical healthcare workers (51.7% vs 23.0%), though, and maybe they were more exhausted and this explains it, but you’d think this would show up in their mental health, too. None of the cases were hospitalized for COVID.
A large study of long COVID in non-hospitalized patients estimated risks and excess burdens of symptoms at 6 months. See Figure 3 where “Positive” indicates “non-hospitalized individuals with COVID-19″. Dividing the excess burdens by 1000, fatigue looks like <2%, and they’re all < 2.5%. EDIT: I misread; they’re not checking whether they still have the symptoms only at 6 months, but whether they have them at any point 30 days to 6 months post-infection. From the paper:
Outcomes were ascertained from day 30 after COVID-19 diagnosis until the end of follow-up.
My best guess is that you have at least an additional ~1% risk of fatigue lasting > 6 months (and who knows how long) if you’re vaccinated and catch COVID than if you don’t catch COVID at all. My upper estimate is around 10%, but as I mentioned above, I give more weight to lower estimates, since I expect them to be less biased.
Re: the healthcare workers study. This seems like one of the best studies because of the matched control group and the fact that it’s median 7.5 months after people had Covid. My main takehomes from this study:
1. 3% of Covid cases self-described has having ongoing symptoms at least 6 months out. This is only 4 people and so error bars are large. The inferred prevalence would be lower for men as this sample is skewed to women. 11% of cases had sporadic symptoms, but this seems significantly less bad than ongoing symptoms.
2. There were differences in between Covid cases and controls in self-reported symptoms that weren’t picked up by (1). The really big affect is loss of smell/taste (which I don’t see as very concerning). The neurological effects MichaelStJules cites seem less concerning. 15% of people without Covid are complaining of brain fog and 28% with Covid. I’m a bit puzzled about 15% of non-Covid people saying this. But given that they self-describe as having brain fog on (IMO) flimsy grounds, it’s not that surprising that 13% more of Covid cases would report this (even if actual rates were only a few % different). This could be explained by demographic differences in front-line workers vs office/tech staff. Or from people hearing that Covid causes brain fog. Or from having brain fog during Covid and then being primed to notice it.
Some concerns about the study: 1. Selection bias in who filled out the survey (e.g. people who think they have Long Covid more likely to fill out the questionnaire, people with worst cases of Long Covid less likely to fill out survey). 2. The % among non-Covid with neurological symptoms is absurdly high and so it’s clear the self-report methodology is very noisy/confusing. (These are all people employed in healthcare and skew younger so I’d expect serious neurological symptoms to be rare). 3. Different demographics of Covid cases vs non-Covid cases. 4. Only ~100 Covid cases and so can’t detect rare effects. 5. The survey asked explicitly about Long Covid and so primed people about it. 6. These healthcare workers who had Covid all knew they had it (lab confirmed). An ideal study would look at people who never got a positive test. 7. They excluded people who had Covid less than 6 months ago. That might induce some bias for prevalence estimates (but not sure).
The high prevalence of neurological symptoms could be related to working in healthcare during a pandemic. Mental health also looked bad, but didn’t differ significantly between cases and controls.
(1) Prior to covid, I was underrating how risky it is to get sick, because I was not accounting for the risk of chronic illness. I needed to update that prior, and take more general precautions against getting sick, period.
(2) Because chronic illness is not a unique or even (apparently) particularly special risk of COVID, fear of chronic COVID specifically should not change my risk calculus or precautions overall.
So I am simultaneously being more careful than I was before the pandemic, and less careful than my friends who still think “long COVID” poses a unique and novel threat that requires extra-special risk avoidance.
I think long COVID is particularly bad because I think you are much more likely to get it from pretty normal activities if you’re not careful. Lyme disease, which the author of that comment mentions (citing this article), also looks common:
Recent estimates using other methods suggest that approximately 476,000 people may get Lyme disease each year in the United States.
I would guess that there aren’t that many others nearly as bad, but I haven’t really looked into it. I think colds, flus and food poisoning are much less severe and less common than COVID-19.
I also worry that it could become basically chronic and lifelong. It’s surprising that we still presumably see effects 6 months after, and if 6 months isn’t long enough to get better, that’s reason for me to believe that these people won’t get better. And it’s possible to catch COVID multiple times (although you become more immune each time), so each time you may face a risk of long COVID.
If they do longer studies, maybe we’ll see more people getting better, and with future studies, we’ll have more reliable statistics. For now, I plan to continue being somewhat cautious and avoid large indoor crowds and high-traffric indoor areas.
When you say that each consecutive time you catch covid you become more immune, do you implicitly estimate that each consecutive infections comes with lower risk of long covid?
This is what I was thinking, yes. The vaccines themselves reduce your risk of long COVID conditional on catching COVID, and more vaccines seem to be better (even after 2).
On the other hand, maybe there could be cumulative damage from repeated infections and there’s some kind of threshold effect.
There wasn’t much discussion of long COVID here. At what risk of long Covid (including possibly chronic fatigue and brain fog lasting >6 months, up to the end of study periods, and possibly much longer) would you change your mind about this? I suppose it would still depend on your personal preferences, and how much you get out of certain activities (enjoyment and mental and physical health).
In my specific case (in Canada), I’ve decided to move out of my current dorm-style residence, since although it’s pretty empty now, I would have been sharing a kitchen with 17 other people (although I’ve been told less than half of residents ever really use the kitchen), and a bathroom with 3 other people. I’d also expect there to be parties with outsiders here, too. I think it’s likely that almost everyone would be vaccinated, though.
I think the evidence is somewhat ambiguous on long COVID rates at this point, even among the studies with actual comparisons/controls. A few of the higher quality studies with comparisons/controls were discussed here:
https://www.nature.com/articles/s41591-021-01292-y
https://jamanetwork.com/journals/jama/fullarticle/2778528
https://www.medrxiv.org/content/10.1101/2021.03.18.21253633v2.full-text
https://www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/conditionsanddiseases/bulletins/prevalenceofongoingsymptomsfollowingcoronaviruscovid19infectionintheuk/1april2021
I’d somewhat lean towards lower risk estimates, since I think higher ones are more likely to be biased due to poorly matched controls, selection bias or unrepresentative samples. On the higher end of studies with controls, one of them (of healthcare workers) had small/insignificant differences in mental health between positive and negative cases, but (most worrying to me)
See Table 2. Positive cases were more likely to be patient-facing frontline clinical healthcare workers (51.7% vs 23.0%), though, and maybe they were more exhausted and this explains it, but you’d think this would show up in their mental health, too. None of the cases were hospitalized for COVID.
See also this post on vaccination and long COVID and this post in Bountied Rationality on Facebook.
From the Bountied Rationality post, these two were shared, among others:
In a (small) sample of 39 breakthrough infections among fully vaccinated healthcare workers, 19% had symptoms lasting > 6 weeks. I haven’t gone through in detail, but it doesn’t look like they had a comparison group for this one.
A large study of long COVID in non-hospitalized patients estimated risks and excess burdens of symptoms at 6 months. See Figure 3 where “Positive” indicates “non-hospitalized individuals with COVID-19″. Dividing the excess burdens by 1000, fatigue looks like <2%, and they’re all < 2.5%. EDIT: I misread; they’re not checking whether they still have the symptoms only at 6 months, but whether they have them at any point 30 days to 6 months post-infection. From the paper:
For another analysis, see this comment.
My best guess is that you haveat leastan additional ~1% risk of fatigue lasting > 6 months (and who knows how long) if you’re vaccinated and catch COVID than if you don’t catch COVID at all. My upper estimate is around 10%, but as I mentioned above, I give more weight to lower estimates, since I expect them to be less biased.Re: the healthcare workers study. This seems like one of the best studies because of the matched control group and the fact that it’s median 7.5 months after people had Covid. My main takehomes from this study:
1. 3% of Covid cases self-described has having ongoing symptoms at least 6 months out. This is only 4 people and so error bars are large. The inferred prevalence would be lower for men as this sample is skewed to women. 11% of cases had sporadic symptoms, but this seems significantly less bad than ongoing symptoms.
2. There were differences in between Covid cases and controls in self-reported symptoms that weren’t picked up by (1). The really big affect is loss of smell/taste (which I don’t see as very concerning). The neurological effects MichaelStJules cites seem less concerning. 15% of people without Covid are complaining of brain fog and 28% with Covid. I’m a bit puzzled about 15% of non-Covid people saying this. But given that they self-describe as having brain fog on (IMO) flimsy grounds, it’s not that surprising that 13% more of Covid cases would report this (even if actual rates were only a few % different). This could be explained by demographic differences in front-line workers vs office/tech staff. Or from people hearing that Covid causes brain fog. Or from having brain fog during Covid and then being primed to notice it.
Some concerns about the study:
1. Selection bias in who filled out the survey (e.g. people who think they have Long Covid more likely to fill out the questionnaire, people with worst cases of Long Covid less likely to fill out survey).
2. The % among non-Covid with neurological symptoms is absurdly high and so it’s clear the self-report methodology is very noisy/confusing. (These are all people employed in healthcare and skew younger so I’d expect serious neurological symptoms to be rare).
3. Different demographics of Covid cases vs non-Covid cases.
4. Only ~100 Covid cases and so can’t detect rare effects.
5. The survey asked explicitly about Long Covid and so primed people about it.
6. These healthcare workers who had Covid all knew they had it (lab confirmed). An ideal study would look at people who never got a positive test.
7. They excluded people who had Covid less than 6 months ago. That might induce some bias for prevalence estimates (but not sure).
The high prevalence of neurological symptoms could be related to working in healthcare during a pandemic. Mental health also looked bad, but didn’t differ significantly between cases and controls.
One perspective on this, from a comment on the SSC reddit:
I think long COVID is particularly bad because I think you are much more likely to get it from pretty normal activities if you’re not careful. Lyme disease, which the author of that comment mentions (citing this article), also looks common:
I would guess that there aren’t that many others nearly as bad, but I haven’t really looked into it. I think colds, flus and food poisoning are much less severe and less common than COVID-19.
I also worry that it could become basically chronic and lifelong. It’s surprising that we still presumably see effects 6 months after, and if 6 months isn’t long enough to get better, that’s reason for me to believe that these people won’t get better. And it’s possible to catch COVID multiple times (although you become more immune each time), so each time you may face a risk of long COVID.
If they do longer studies, maybe we’ll see more people getting better, and with future studies, we’ll have more reliable statistics. For now, I plan to continue being somewhat cautious and avoid large indoor crowds and high-traffric indoor areas.
Given that the SARS side-effects were still there years later there’s nothing surprising about still seeing effects 6 months later.
But the IFR for SARS is order of magnitudes higher and we know that severe illness is more likely to cause long-term effects.
An order of magnitude less then SARS would still be a lot.
How do we know that? We did have some long-COVID studies that suggest this isn’t the case.
If the long-term effects are due to the immune system “learning” to attack native cells that can happen without severe illness.
When you say that each consecutive time you catch covid you become more immune, do you implicitly estimate that each consecutive infections comes with lower risk of long covid?
This is what I was thinking, yes. The vaccines themselves reduce your risk of long COVID conditional on catching COVID, and more vaccines seem to be better (even after 2).
On the other hand, maybe there could be cumulative damage from repeated infections and there’s some kind of threshold effect.
I’ve edited my comment, since I misinterpreted one of the studies. See also this comment and this separate estimate based on different studies.