Does covid cause brain damage?

covid head brain damage

The latest in the long succession of attempts at maximizing people’s fear of covid is the claim that it causes brain damage. And not just in those who have spent time in the ICU, in everyone, even if all they had was a mild cold. The claim is currently doing the rounds on social media (apparently alarmist propaganda only counts as misinformation if it’s going against the dominant narrative). The assertion comes from a paper that’s recently been published in EClinicalMedicine (a daughter journal of The Lancet). The paper is actually quite illuminating about the current state of medical research, so I thought it would be interesting to go through it in some detail.

81,337 individuals residing in the UK completed an on-line test of their cognitive function. They also provided information on their covid status (whether or not they thought they’d had it, and how sick they were), as well as a bunch of other demographic information. The data was collected from January to December 2020.

12,689 (16%) of the 81,337 participants indicated that they thought they had had covid-19. They were sorted by the researchers in to five categories based on the severity of disease, from “ill without respiratory symptoms” to “hospitalised and on a ventilator”. The results from these five categories were then compared with the results from the 68,648 people that didn’t think they’d had covid.

The reason the study is causing such a stir is because of the results. All five of the “I think I’ve had covid” categories performed worse on the cognitive function test than the “I don’t think I’ve had covid” category did. The reduction in performance was correlated with the severity of disease, with the people who had been on a ventilator performing worst – according to the researchers their results were equivalent to a seven point reduction on an IQ test. If we assume that the non-covid group have an IQ of 100, this would mean that the group that had been on a ventilator have an IQ of 93.

Ok, open and shut, right? Having covid makes you more stupid, and the more severe disease you have, the more stupid you become. Well, not quite.

The first thing that needs to be pointed out is that this was an observational study. Observational studies cannot usually say anything about cause and effect, because the participants haven’t been randomly assigned to the different groups (as they would have been in a randomized controlled trial). The inability to draw any conclusions about cause and effect is especially true when the difference between the groups is small, as it is in this study. There could well be major underlying differences between the groups that explain the differences in performance on the cognitive function test.

When we go through the demographic data, we see that this is actually the case, in particular when it comes to chronic conditions. Chronic liver disease (such as for example liver cirrhosis) was more common in those who thought they had had covid, and the relative rate increased the more severely sick people had been with covid. Chronic lung disease (such as COPD) and chronic kidney disease also co-varied with severity of covid. These underlying illnesses could on their own confound the results enough to explain the differences in cognitive performance seen in the study. People with underlying chronic diseases have worse cognitive function, and they’re also more likely to become severely ill if they get covid. Just because you see a correlation doesn’t mean there’s a cause and effect relationship!

The groups also varied in terms of the proportion in each category that had ADHD. The people who didn’t think they’d had covid were less likely to have ADHD than the people who thought they’d had covid. Oddly, severity of disease correlated quite closely with the probability of having ADHD. This matters, because it’s likely that people with ADHD will underperform on many parts of a cognitive function test. If the researchers wanted to, they could have interpreted this as showing that covid causes ADHD. But they didn’t, because that would be silly. Yet the exact same logic (correlation between two variables in observational data) was used to claim that covid causes brain damage.

It’s worth noting that for all the possible confounding factors that the authors of the study have asked the participants about and tried to account for, there are many more that they haven’t asked about, and that could also explain the results seen in the study. Confounding isn’t something that should be taken lightly, which is why conclusions about cause and effect shouldn’t be drawn from purely associational data.

The second thing that needs to be pointed out is that this study was cross-sectional. In other words, participants only had their cognitive function tested at one time. That in itself makes it impossible to say anything about whether the participants performance decreased after having had covid, because we have no idea what their performance was before they got covid. If you want to know if something has changed over time you need to do a longitudinal study, where you test people multiple times.

The fact that the study was observational and cross-sectional, and that there were big underlying differences between the groups, is on its own enough to disqualify any claims about this study being able to show that covid causes brain damage. But it gets worse. A lot worse.

A major problem with the study is that 97%(!) of the people who thought they’d had covid lacked testing to confirm the diagnosis. Of the 12,689 that thought they’d had covid, only 386 actually had a confirmed diagnosis. The only group in which the majority actually had a positive test confirming that they had had covid was the group that had been on a ventilator in an intensive care unit! If you can’t even be sure that 97% of participants actually had the disease you’re trying to draw conclusions about, then you really don’t have a leg to stand on.

I think it’s worth remembering that, even during the covid peak, only around 20% of covid tests were coming back positive. In other words, even when covid was spreading at its most rampant, most people who had a respiratory infection did not have covid. They had something else. It is therefore reasonable to think that at least 80% of the 97% (i.e. at least 78% of participants) that think they had covid, did not in fact have it. What that means is that the study is rubbish, and cannot make any claims about covid whatsoever. Yet it does. And it’s been published in a peer reviewed journal.

To me, the main lesson here is that we currently live in a world where junk science goes unquestioned and gets published in peer-reviewed journals as long as it feeds in to the dominant narrative. If this study had been claiming, say, that face masks didn’t work, then it would remain stuck at the pre-print stage forever, or, if it ever did get published, it would immediately have been retracted. It has become blatantly obvious over the past year and a half that it is not primarily the quality of studies that determines where and whether they get published, but rather their acceptability to the powers that be.

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64 thoughts on “Does covid cause brain damage?”

  1. thank you so much, Sebastian, for your intelligent and clear writing. A rare beacon of light in an increasingly bonkers world.

  2. Prolonged stress (isolation, anxiety, helplessness) can be cognitively debilitating. The response by governments to, and the fear produced by, the virus are as likely to disrupt brain function as the virus itself.

    1. Absolutely agree. I rate your comment tops. Prolonged fear and restrictions damage multiple aspects of health, physical as well as mental.
      I ignore MSM because it promotes stuff on ‘social-networking’ sites, in the guise of refuting it. If I wanted to know what’s on those sites, I’d join them; I haven’t.
      Repeating rubbish gives it substance it does not itself have. It should be ignored as being of no account, left as it is.
      When articles on this site were more infrequent, their quality was good. Recently, they’ve seemed lesser quality rapidly churned out.

  3. No surprise to me that fear-mongering over covid is progressing at an alarming rate. The amount of disinformation and outright lying that is being published as fact crosses all areas of research and it is nearly impossible to believe much that is coming out in MSM journals.

    Currently, in order to sit inside a restaurant in Portugal one must present proof of vaccination or a negative test! Otherwise al fresco dining is the only alternative. The same applies to staying in a hotel. At least hotels are selling self-tests for around 3Euros that one does in front of the desk clerk.

    What’s next? Maybe we will be required to wear an identifying badge or tattoo….

    1. Even worse here in France. From Aug 9th you won’t be able to eat inside or outside in any restaurant, or have a drink in a bar or go for a coffee without a “passe sanitaire” . This is either proof of vaccination, proof of recovery from covid ( but only in the last 6 months) or a negative test in the last 48 hrs. Tests become payable in autumn – 50euros for a PCR test. Nor will you be able to get any hospital treatment other than emergency. It’s to force people to get the vaccine by making their life really difficult if they don’t.

  4. I always glad when I see a blog from you.
    This completely mad world need people like you.

    I share your blogs everywhere I can.

  5. From the paper, the lead author is associated with Imperial College, which sadly at the moment is enough on its own to discredit a piece of medical research.

  6. Sebastian you are like a ray of very welcome sunshine in this seemingly endless doomladen Covid messaging and responses especially from the UK government. We seem to have lost all sense of perspective in a crisis which shows no sign of ending.
    Keep up the good work.
    Michael

  7. Bravo, Sebastian!
    You are so right. The last paragraph perfectly summarises the current state of affairs in the scientific publishing industry. Incidentally I managed to published one the very few papers that were not pro-mask in the post-covid era. It is a small paper that shows that the probability of viral transmission outdoors, using bacteriophages as surrogates, is very low, thus implying that mask wearing outdoors is completely unnecessary. (Not that indoors masks have much of an effect).
    Even though the message of the paper was quite mild, it was not easy getting the paper published in a scientific journal.
    Link to the paper: https://pubmed.ncbi.nlm.nih.gov/34046704/

  8. Another covid post? I don’t really care much about the disease anymore, but I am concerned about the authoritarian attempts to use fear about covid to control people.

    “A major problem with the study is that 97%(!) of the people who thought they’d had covid lacked testing to confirm the diagnosis. Of the 12,689 that thought they’d had covid, only 386 actually had a confirmed diagnosis. The only group in which the majority actually had a positive test confirming that they had had covid was the group that had been on a ventilator in an intensive care unit! If you can’t even be sure that 97% of participants actually had the disease you’re trying to draw conclusions about, then you really don’t have a leg to stand on.”

    What does “had covid” mean? Exposure? Symptoms? What assurance does “confirmed diagnosis” offer if most doctors are likely to misdiagnose influenza as covid based on overcycled PCR?

    What assurance does being on a vent offer? Influenza patients can end up on vents.

    What are the clearest indicators of covid? Invisible hypoxia? Elevated D-dimer levels? Elevated IL-6 levels? Bilateral ground glass opacities in lung scans? Seriously, does covid have to progress before we can say that we’ve had it? That seems like an awful solution. And maybe some of us will never be able to reach that “goal” because our immune systems are too competent.

    I would expect every covid patient’s systems (lungs, kidneys, liver, brains, etc.) to show damage from covid because every system relies on capillaries and capillaries are invariably damaged in covid.

    This article is thrashing about in quicksand–and so was the EClinical article. The good news is that there’s still great opportunity to thrash about in quicksand. (Sure, a PCR test can possibly show exposure, except when false negatives occur.)

    I’m smiling as I write this.

    “It has become blatantly obvious over the past year and a half that it is not primarily the quality of studies that determines where and whether they get published, but rather their acceptability to the powers that be.”

    I couldn’t agree more.

  9. I’m surprised you didn’t discuss the reverse cause and effect possibility. The same data could be used to “prove” that having cognitive brain injury causes people to think they have a case of Covid-19.

  10. “The fact that the study was observational and cross-sectional, and that there were big underlying differences between the groups, is on its own enough to disqualify any claims about this study being able to show that covid causes brain damage. ”

    And yet Covid incentives clearly cause brain damage in medical researchers.

  11. I used to do some peer reviewing for anaesthesia publications. This article is a disgrace. The discussion section is supposed to discuss the limitations of the study, and there is barely a mention of the problems listed by Dr Rushworth in the published paper. One aspect that might be relevant is that the journal charges $3500 for accepted papers. so maybe money talks.

    1. The journal should up its prices, to keep science out of the hands of riff-raff like academia and those of us in the peanut gallery and to keep research properly in the hands of pharma. I’m certain pharma wouldn’t mind paying even 35,000 to get an article published to keep regulatory and research capture.

  12. It’s hard to imagine that “science” this poorly executed got published anywhere at all, but in the baby sister to The Lancet? Mind you The Lancet has produced some pretty dodgy “pro-the-current-narrative” publications recently…

  13. The interesting study would be cognitive damage post vaccination due to the microclots in the brain. Dr Peter McCollough is convinced by the number of his patients presenting with neurological damage that it will be a medium to long term problem. He has an interview over on conservativewoman.

    On the other hand Boris Johnson could be an n=1 confirmatory study of declining mental acuity post ICU that might be easily proven by examination of his increasingly garbled speeches on everything – but then he claims to have visited the Jabberwock as well so who knows.

    1. Indeed, the covid vaccines are likely to cause cognitive decline due to blood clots. Even micro clots could noticeable issues.

  14. “Having covid makes you more stupid, and the more severe disease you have, the more stupid you become.”
    On that basis, I would estimate that most of Western civilisation has had severe Covid. Mind you, that has to be a major plus for Herd Immunity.

    /sarc end.

    1. Yes, but for the sheeple that obey all the rules cast down upon them–they will be given Herd Impunity…..

  15. Much truth in this, especially the muzzling of research and opinion that runs counter to the establishment, as I too have found. I have also found it galling that despite my many attempts the media have also chosen not to return my calls.

    That said there is brain damage caused by Covid-19; first, there may be a cerebral vasculitis (blood vessel inflammation) or abnormal clotting in the cerebral vessels. This is well-documented. Second, “Long Covid” is in all probability an autoimmune phenomenon which produces fatigue, memory issues and the like in much the same way as one sees in autoimmune rheumatic disorders such as rheumatoid arthritis and lupus (SLE).

    Sebastian is quite right to be highly suspicious of any study which relies on uncorroborated observational evidence. Knowing if you have had Covid-19 without appropriate tests is akin to knowing you have had side-effects from a drug in a randomised trial – where you may get side-effects despite being in the placebo group.

    I would yet again make a plea to distinguish infection with SARS-CoV-2 (which can be asymptomatic or have minimal symptoms) from Covid-19. This latter term strictly should refer to the hyperimmune state induced by the virus, making you seriously ill and with clearcut test evidence -thus being a subset of SARS-CoV-2 infection – although an identical syndrome can be produced by other viruses and by some drugs, as well as arising spontaneously due to a genetic anomaly..

    1. Perhaps the “hyper-immune state” could also be called “immune deficiency syndrome”, where people are somewhat deficient in vitamin D and/or zinc.

      ” Effects of a 2-Week 5000 IU versus 1000 IU Vitamin D3 Supplementation on Recovery of Symptoms in Patients with Mild to Moderate Covid-19: A Randomized Clinical Trial ”

      https://www.mdpi.com/2072-6643/13/7/2170

      1. Strictly immune deficiency means the immune system doesn’t work, whereas in COVID-19 it works too well. But it’s possible that vitamin D and/or zinc deficiency reduce modulation or alter the ability of the coronavirus spike protein to stimulate it. I don’t know but I expect a rational explanation will emerge eventually.

      2. What do you call a condition where the immune system doesn’t work properly because of deficiencies in vitamin D and or zinc?

    2. Dr Bamji,

      Enjoyed your book. I wonder if you’ve considered that covid has been the 1755 Lisbon earthquake for us peasants. Our sinfulness did not bring on the earthquake by refusing to wear masks and shun our family. You priests and your church have lost credibility. Every study, diagnosis, theory is just one more indulgence we have to pay for. Western chattering classes are desperate for an Ahnenpass 2.0.

    3. Whether “Long Covid” is real or not, our president Joe Biden has (last week) directed Federal agencies to include it under the Americans With Disabilities Act (ADA). This of course opens up the floodgates for all sorts of suits wrt to employers making “reasonable accommodations” and claims for disability via SSI and other such government agencies. Details being worked up, but I suspect one of them with *not* be proof of prior covid infection.

    1. it’s all about the money.
      govies just gave the vax guys $4 billion for another 200mm vaccine doses.
      at the same time the govies, via law, removed liability and accountability from the vax makers. that means full speed ahead, because there will be no personal or corporate liability for the damage that has been done and will be done. so in exchange, the vax makers will be giving huge donations to the politicians’ PACs. and the vax makers are providing hundreds of millions of dollars in advertising to the MSM, who continue to push for vaccinations even to the point of making them mandatory. that’s it in a nutshell.

  16. “If this study had been claiming, say, that face masks didn’t work, then it would remain stuck at the pre-print stage forever, or, if it ever did get published, it would immediately have been retracted. It has become blatantly obvious over the past year and a half that it is not primarily the quality of studies that determines where and whether they get published, but rather their acceptability to the powers that be.”

    That excellent (if I may say so) observation is Exactly what I posted on the New York Times site a few minutes ago. It will not get posted. I posted many others today with my usual cites, data, links, and smart person quotes – and they all got taken down after being initially posted. I guess they came to their senses.

    I was correcting their misinformation with actual facts and mainstream power hates that. Most of the well programmed commenters on the NYT also hate my posts, although they rarely check out my sources. They just want to parrot the party line. Both Trumpsters and Liberals are equally enamored of their ideology – and truth is irrelevant, in fact truth is an existential enemy that must be crushed.

    The mainstream is the primary purveyor of misinformation and this is a global initiative. If you question the narrative, you get disparaged.

  17. Another great piece, Sebastian. I want to become a patron, but I do not want to sign up for monthly charges. Is there any way I can pre-pay a year or two, or make a lump sum payment?

  18. Sebastion I am shocked. I didn’t even need to read right through your post to know how flawed the study was. That is without any statistical or medical training. A high I.Q. yes but basically common sense!
    And the journal the so called study appeared in was a ‘sister’ to the Lancet!
    Keep up your good work please. Topple the whole Covid19 Scamdemic empire because the whole world is becoming a Covid Dictatorship.

  19. before 2020 the number of brain damaged people coming out into the open seemed a lot lower for sure.
    so either the number rose or maybe they became more visible.

  20. Another interpretation could be that those with lower cognitive ability are more likely to think they have had Covid

  21. To date, I still don’t know of anyone who got sick or died from this Wuflu. However, a few friends claim to know people who did get sick and who claimed that it was so terrible that at the time they wished they would die! While I am not acquainted with any of these affected people, I’ve heard enough about their behavior to seriously doubt their claims. They definitely define “lower cognitive ability” in their day-to-day actions.

    I also see another factor at work here, the desire to be the center of attention. This is another form of mental instability, IMO. One sure way to get attention from one’s circle of friends and acquaintances is to claim to be a surviving victim of Wuflu or suffering from Long Covid.

  22. Thank you Sebastian for another great post! You seem sick and tired of the lies and propaganda.

    It’s apparent now the vaccines are extremely dangerous- FAR more dangerous than COVID itself. I bet a lot of COVID “cases” and deaths are actually due to the vaccines.
    https://uncoverdc.com/2021/07/26/informed-consent-afld-lawsuit-seeks-halt-to-eua-and-fda-approval/

    https://trialsitenews.com/wp-content/uploads/2021/07/Vaccine-safety-FAQ-1.pdf

    No one should wonder why so many people are vaccine hesitant. The real question is why governments world-wide are frantically trying to vaccinate EVERYONE. Here is one possible answer:
    https://www.conservativewoman.co.uk/the-pandemic-lies-according-to-piers-corbyn/

    1. I think you need better evidence than these 2 references to support your statements. I generally take the view that if I read something that I know to be nonsense, then the rest of the article has to be disbelieved until proven true.
      The first reference repeats the nonsense claim that there is an 82% first trimester miscarriage rate after vaccination.
      The second reference is an interview with Piers Corbyn. While he has political views that many people will disagree with (but not me), he is a well known crank for his views on the climate and weather, claiming he can predict earthquakes and volcanic eruptions from solar activity. His views on Covid are just bizarre.

      1. Just remember- someone can be 100% wrong about one issue and yet 100% correct about something else.

  23. If those who thought they’d had covid, without any supporting data, scored lower on an intelligence test than those who didn’t think they’d had covid*, then I wouldn’t be so fast to dismiss the results out of hand.

    My hypothesis is that fear of covid makes people stupid. There seems to be a wealth of observational data supporting this hypothesis and this may be just one more example. Even seemingly intelligent people with a fear of covid seem to drop remarkably in intelligence. This should be a testable hypothesis.

    Yes, I am being a bit flip, but not really.

    *I’m assuming no one in this group thought they were asymptomatic covid cases and that those that did volunteered for the first group

  24. Thank you very much!
    i am very grateful for your important enlightening work! It is very valuable in these times.

  25. Have you written anything on the comparison between vaccinated and non vaccinated people in terms of transmission. Are vaccinated people less likely to carry or pass on covid?

  26. Antivaxxers at the CDC reporting about Barnstable County, Massachusetts…69% double-vaxxed…74% of new covid infections…

    https://www.documentcloud.org/documents/21030483-outbreak-of-sars-cov-2-infections-including-covid-19-vaccine-breakthrough-infections-associated-with-large-public-gatherings-massachusetts-july-30-2021

    Of course, they repeat the standard pap about vaccines working (despite no good scientific evidence supporting their claim).

    The EUA for the vaccines was based on studies claiming 90-95% relative efficacy at preventing transmission, but that’s not what the data in the field is showing now. If anything, vaccination predisposes people slightly to infection.

  27. 20% of those tested have had covid, meaning that 80% have hd something else…
    On condidtion that only people with symptoms have been tested. Was that the case? Not herr in Austria though. We tested (and still do) asymptomatic people like maniacs.

  28. If it would be not too much to ask… could you look into the evidence on vaccines and pregnant mothers? In my country they are heavily pushing pregnant women to get vaccinated with eithet Pfizer or Moderna, because delta variant is supposedly soo dangerous for pregnant women
    And after all the nonsense that is going onI am skeptical.
    This is personal, as a close relative is pregnant right now. Could you shed some evidence based light on this matter?

  29. I looked at the CDC report on a covid Delta Variant outbreak in Barnstable County, Massachusetts. From the data, it looks like the fully-vaccinated have a 1.28 relative risk of covid infection compared to the not fully-vaccinated.

    Maybe this is why the CDC is now saying that the vaccinated need to mask.

    More details in a post on my blog.

  30. Data point.

    Covid cases in my county spiking because of a huge wave of immigration and summer vacation travel. New hospitalizations and deaths still very low–one “covid” death per week in my county. Hospitalizations are mostly for observation and most go home within a few days.

    (“Cases” means “exposure within the last 5-6 weeks.”)

    Good news.

  31. “Fake News” Kestin 😉 and the “1.44” US R-value

    As I said, the “surge” is coming from immigrants. There are two main purposes of a border–jurisdiction (political and legal) and public health. When the political leaders fail to enforce a border, public health suffers. Hopefully, most of the cases are the immigrants and my hypothesis about indigenous herd immunity is correct. 260,000 immigrants in July captured and released…an estimated 750,000 evaded capture…20% positive testing rate…the estimated 200,000 infectious immigrants (from July alone!) will certainly cause some indigenous people to catch covid and die…not a peep from the CDC about this…shock!

    “Texas Borderland Doctor States the Obvious: The COVID Surge Is Coming From Biden’s ‘Grossly Irresponsible’ Border Policies”

    https://pjmedia.com/news-and-politics/bryan-preston/2021/08/08/texas-borderland-doctor-states-the-obvious-the-covid-surge-is-coming-from-bidens-grossly-irresponsible-border-policies-n1468007

  32. One detail that has been overlooked is the potential for the mRNA for the spike protein to be reverse transcribed into DNA, and be incorporated into our cell’s DNA. If it’s true, then our cells have the ability to produce the spike protein indefinitely, and their descendants will have the same phenotype. This could result in chronic immune responses to the spike protein, causing a host of symptoms. Nobody is paying attention to this potential phenomenon. I think we should be.

  33. Data point from my metro…

    2nd hand from an ICU nurse…

    covid patients age 20-40 from rural areas and unvaccinated predominate in her ICU, with some deaths and no comorbidities

    vaccinated patients still predominate in hospitals

    deaths averaged one per day last week (not high compared with Nov.-Dec. 2020), but those dying are young and middle-aged…mostly Delta

    maybe van Bossche was correct about the leaky vaccines putting the unvaccinated at risk

    IM Doc over at NakedCapitalism says that he is treating outpatients early with ivermectin and seeing good results as he tracks patients and calls them twice a day about symptoms

  34. Dr. Rushworth,

    Is giving calcifediol for covid standard protocol for covid in Sweden? Can you provide your analysis of studies of calcifediol for covid?

    My non-medical analysis is that it is at worst benign and may be beneficial. But I would also like to hear what _you_ have to say.

    You might have seen the following already, but maybe some other people haven’t yet.

    “Based on the results of nine RCTs comparing physiologic doses of oral cholecalciferol with oral calcifediol, calcifediol was 3.2-fold more potent than oral cholecalciferol. Indeed, when using dosages ≤ 25 μg/day, serum 25OHD increased by 1.5 ± 0.9 nmol/l for each 1 μg cholecalciferol, whereas this was 4.8 ± 1.2 nmol/l for oral calcifediol. Third, oral calcifediol has a higher rate of intestinal absorption and this may have important advantages in case of decreased intestinal absorption capacity due to a variety of diseases.”

    https://pubmed.ncbi.nlm.nih.gov/29713796/

  35. I raised the points in this article to challenge a column by a media backed microbiologist, and I was just wondering what your thoughts were on her response. Here is the original column:https://www.stuff.co.nz/national/health/coronavirus/300369642/covid19-infection-causes-worrying-brain-changes

    Below is the response from that microbiologist:
    I have a 500-word limit which means that it wouldn’t have been possible to cover off all the points raised below. By describing the Great British Intelligence Test as I did, “a citizen science project” that “wasn’t a traditional IQ test, but was designed to measure things like spatial planning, problem-solving abilities, and short-term memory capacity…” and that “inadvertently provided an extremely useful dataset to look at the potential impacts of Covid-19 infection on the brain”, I believe I have clearly indicated that this was not a randomised controlled trial. I also made it clear that the study was comparing between groups, not the scores of people before and after they had COVID-19.

    This study did not compare pre and post COVID test scores and was not designed to measure IQ. As the researcher’s don’t know what has happened to each individual’s test scores before and after infection this wasn’t discussed in my piece. Instead, I talked about the results of the study which was comparing people who reported having COVID-19 (either confirmed or suspected).
    In the early part of the pandemic when this study was done, access to COVID-19 testing wasn’t available to people in the UK who weren’t hospitalised. This is why the number of confirmed cases is so low compared to people who reported experiencing COVID-19 symptoms.

    It is true that observational studies don’t establish cause and effect but instead point to important things that should be further studied. That is why I pointed out the need for further research in the area.

    The effect size wasn’t small but did vary between the different tests. In the first draft of my column, I included this but had to remove it due to the word limit.

    The 80,000 people who are reported on in this paper and my column are part of a larger study with another 270,000 people. The only thing that is different about the 80,000 is that they took part in the study in May which was when the pandemic-related questionnaire was added. It’s always a possibility there was some other underlying differences between the people who joined in May and said they had COVID-19 related symptoms versus those that also joined that month and didn’t have symptoms, though I don’t believe it is unreasonable to suggest that the difference between the groups was COVID-related given what was happening in the UK at the time. The number of participants was certainly sufficient to control for the usual factors that can confound these sorts of studies, like age, education, socio-economic factors, and underlying health conditions.

    Chronic liver disease (such as for example liver cirrhosis) was more common in those who thought they had had covid, and the relative rate increased the more severely sick people had been with covid. Chronic lung disease (such as COPD) and chronic kidney disease also co-varied with severity of covid. These underlying illnesses could on their own confound the results enough to explain the differences in cognitive performance seen in the study. People with underlying chronic diseases have worse cognitive function, and they’re also more likely to become severely ill if they get covid. Just because you see a correlation doesn’t mean there’s a cause and effect relationship.

    This point is rebutted by the authors in the discussion of the paper: “The observed deficits varied in scale with respiratory symptom severity, related to positive biological verification of having had the virus even amongst milder cases, could not be explained by differences in age, education or other demographic and socioeconomic variables, remained in those who had no other residual symptoms and was of greater scale than common pre-existing conditions that are associated with virus susceptibility and cognitive problems (my emphasis)”.

    I can’t answer this one. I don’t know enough about the tests to say whether this is true or not. The tests were optimised for older people and those with mild cognitive and motor impairments. The researchers could look at this in the bigger study, but that wasn’t the point of this study.

    It’s not a surprise that those who had been on a ventilator in intensive care were the ones most likely to have been confirmed as having COVID-19. In the early part of the pandemic when this study was done, access to COVID-19 testing wasn’t available to people in the UK who weren’t hospitalised. The two charts below show that well, with the correlation between confirmed cases and deaths not the same during the first peak as for later peaks.
    I think its also worth noting that this is one of many studies that is pointing to the potential for long term impacts from infection with the SARS-CoV-2 virus. Some studies will certainly be more robust than others, though none will be the kind of randomised-controlled trial that we would rely on for other kinds of research, mainly because those kinds of trials would be unethical. That’s why we look at different forms of evidence coming from different types of studies.

    This will certainly be important to look at as the pandemic progresses.

  36. In my county, covid hospitalizations peaked the week of 8-1 and declined the following two weeks to 30% below the peak. Deaths declined from 13 the week of 8-8 to 2 the past week.

    This looks like good news and pretty much endemic numbers.

    I imagine that some of the deaths are due to people not having been exposed to alpha and denying that covid is a threat and not bothering to supplement or be prepared to treat it.

    It still looks like my county achieved herd immunity back in Nov. 2020. Summer travel and a wave of illegal immigrants can explain this minor summer perturbation.

  37. It looks like the Astrazeneca covid vaccine causes 251 times the viral load of unvaccinated people based on data from a hospital locked down in Vietnam where the hospital did viral sequencing to determine exposure.

    Astrazeneca uses the same mRNA technology as the Pfizer and Moderna vaccines.

  38. Why do we still care about covid after herd immunity? Because it is being used to oppress us by public policy makers.

    mandated vaccines to work in health care, attend university, etc.

    mandated masks for public transport

    antisocial distancing

  39. How about lung damage and other lasting/permanent effects? I’m wondering how (if) worried a healthy person in his 30s should be. I don’t really care if I’m sick for weeks or even months, but if I have more or less permanently reduced physical or mental health, it’s different

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