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.
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.