Mild Covid-19 Linked to Brain Damage

[Jarvis323]

We've been hearing about brain damage caused by moderate and severe covid. A new study suggests even mild Covid causes brain damage. Pretty scary.

During at least the first few months following a Coronavirus infection, even mild cases of Covid-19 are associated with subtle tissue damage and accelerated losses in brain regions tied to the sense of smell, as well as a small loss in the brain’s overall volume, a new British study finds. Having mild Covid is also associated with a cognitive function deficit.

https://www.nbcnews.com/health/heal...inked-damage-brain-months-infection-rcna18959
https://www.nature.com/articles/s41586-022-04569-5

 

[Astronuc]

Doesn't see so mild.

The wife of a close friend had Covid-19 during December 2020. She still has loss of smell and some taste. We wondered about some pictures of her in early 2021, and she looked ill, as in tired, pale, worn. They apparently were exposed by a healthcare worker who was helping care for his mother. His mother, who was receiving chemotherapy succumbed due to Covid-19.

 

[Ygggdrasil]

There was a thread on this study when it was first posted to a pre-print server:
https://www.physicsforums.com/threads/significant-loss-of-brain-grey-matter-after-covid-19.1004274/

Here is my post from that thread (I have not yet read through the version published by Nature, though through a quick browse, it seems my comments still apply):

After a quickly browsing the paper, I'm somewhat skeptical of the results of the study. The study did comparisons of ~2,000 features from their brain imaging between the two groups, which gives plenty of opportunities to find false positives (potentially an example of p-hacking). Furthermore, the statistically significant differences the paper finds seem quite small compared to normal variation. For example, here are some of the most significant longitudinal group comparison results from Fig 1 of the paper:

https://www.medrxiv.org/content/10.1101/2021.06.11.21258690v1.full.pdf

While these results may be statistically significant differences (at least, assuming they corrected for multiple comparison correction correctly), it's not clear whether these observed differences would be biologically meaningful (i.e. whether the differences are large enough to cause clinically relevant symptoms).

 

[bhobba]

At least the media is getting the info out there. From our daily paper, The Courier-Mail:

'A mild case of Covid-19 can cause "significant" damage to the brain, and the shocking extent of the neurobiological harm has been revealed today in one of the biggest brain-imaging studies since the pandemic hit. Researchers compared brain scans from 785 people aged 51 to 81 before and after mostly mild infections. The findings revealed the virus can cause shrinking of the brain in regions essential for processing smell, memory, cognition and emotion.'

Thanks
Bill

 

[atyy]

Doesn't see so mild.

The wife of a close friend had Covid-19 during December 2020. She still has loss of smell and some taste. We wondered about some pictures of her in early 2021, and she looked ill, as in tired, pale, worn. They apparently were exposed by a healthcare worker who was helping care for his mother. His mother, who was receiving chemotherapy succumbed due to Covid-19.

Did she get vaccinated later? There was some idea that getting vaccinated after you've had long Covid can help (not sure what the status of this hypothesis is): https://www.everydayhealth.com/coronavirus/can-covid-19-vaccines-protect-you-from-long-covid/

 

[atyy]

At least the media is getting the info out there. From our daily paper, The Courier-Mail:

'A mild case of Covid-19 can cause "significant" damage to the brain, and the shocking extent of the neurobiological harm has been revealed today in one of the biggest brain-imaging studies since the pandemic hit. Researchers compared brain scans from 785 people aged 51 to 81 before and after mostly mild infections. The findings revealed the virus can cause shrinking of the brain in regions essential for processing smell, memory, cognition and emotion.'

Thanks
Bill

In line with @Ygggdrasil's comments, it is possible the loss of smell is due to peripheral mechanisms (could be both peripheral and central of course, with the importance of each to be determined).

https://www.sciencedaily.com/releases/2021/05/210512115517.htm
https://www.science.org/doi/10.1126/scitranslmed.abf8396
COVID-19–related anosmia is associated with viral persistence and inflammation in human olfactory epithelium and brain infection in hamsters
Guilherme Dias de Melo, Françoise Lazarini, Sylvain Levallois, Charlotte Hautefort, Vincent Michel, Florence Larrous, Benjamin Verillaud, Caroline Aparicio, Sebastien Wagner, Gilles Gheusi, Lauriane Kergoat, Etienne Kornobis, Flora Donati, Thomas Cokelaer, Rémi Hervochon, Yoann Madec, Emmanuel Roze, Dominique Salmon, Hervé Bourhy, Marc Lecuit, Pierre-Marie Lledo.
Science Translational Medicine, 2021; eabf8396 DOI: 10.1126/scitranslmed.abf8396

 

[Astronuc]

Did she get vaccinated later? There was some idea that getting vaccinated after you've had long Covid can help (not sure what the status of this hypothesis is): https://www.everydayhealth.com/coronavirus/can-covid-19-vaccines-protect-you-from-long-covid/

Yes, the family got vaccinated, but vaccines weren't available for our age group until about April or May of 2021. The couple is several years younger than me. Even with the full vaccine and booster, she still has loss of smell and taste. She looks much better than a year ago. When we saw pictures from Dec. 2020, we thought she might have been treated for cancer or something; she looked so pale and gaunt.

I think some symptoms of COVID-19 are reversible, and that may depend on age, i.e., younger folk can probably recover from neural issues, but the older population 50+ probably will not recover (based on personal experience). If tissue dies because clotting has blocked blood vessels and tissue if deprived of oxygen, then that damage may be unrecoverable, especially in brain and heart tissue.

 

[atyy]

Yes, the family got vaccinated, but vaccines weren't available for our age group until about April or May of 2021. The couple is several years younger than me. Even with the full vaccine and booster, she still has loss of smell and taste. She looks much better than a year ago. When we saw pictures from Dec. 2020, we thought she might have been treated for cancer or something; she looked so pale and gaunt.

I think some symptoms of COVID-19 are reversible, and that may depend on age, i.e., younger folk can probably recover from neural issues, but the older population 50+ probably will not recover (based on personal experience). If tissue dies because clotting has blocked blood vessels and tissue if deprived of oxygen, then that damage may be unrecoverable, especially in brain and heart tissue.

I have no idea what's going on in the brain, but if some symptoms are due to inflammation (etc) in the brain, then if the inflammation resolves, there could be a chance of recovery, despite irreversible tissue death. There can be very few neurological deficits in some brain cancers, even though they destroy huge chunks of brain (eg. Fig, 3 of https://academic.oup.com/brain/article/130/4/898/274231).

 

[atyy]

https://www.biorxiv.org/content/10.1101/2022.03.24.485596v1
Differences in neuroinflammation in the olfactory bulb between D614G, Delta and Omicron BA.1 SARS-CoV-2 variants in the hamster model
Lisa Bauer, Melanie Rissmann, Feline Benavides, Lonneke Leijten, Lineke Begeman, Edwin Veldhuis Kroeze, Peter van Run, Marion P.G Koopmans, Barry Rockx, Debby van Riel
"We observed neuroinvasion into the CNS via the olfactory nerve in D614G-, but not Delta (B.1.617.2)- or Omicron BA.1 (B.1.1.529) inoculated hamsters. Neuroinvasion was associated with neuroinflammation in the olfactory bulb of hamsters inoculated with D614G but hardly in Delta or Omicron BA.1."

 

[Oldman too]

No end to the bad news.

https://www.nature.com/articles/d41586-022-00912-y

https://www.thelancet.com/journals/landia/article/PIIS2213-8587(22)00044-4/fulltext

 

[Godot_]

One point to add:

Both smell and memory are ancient systems - in the evolutionary sense. As is the motivational system (the "executive functions"), And they're pretty closely intertwined - anatomically, too.

Totally makes sense, BTW, as this cerebral system comes from an era when we still were little worms or fish swimming in the ocean. Smell (or taste) would be registered as positive when nutrient rich, and negative when toxic or hinting at predators. So, memorizing where the good smell - and hence food, as well as incentivising moving there, is a plus from an evolutionary viewpoint. As is the reverse in malodorous surroundings: Start running and keep in mind to never get back there...

Also, the "nerve" in the olfactory nerve is somewhat of a misnomer. There's no ganglion, where the afference (=input) is filtered and preprocessed, as you'd see in all true nerves - It's actually a part of the brain itself, open to the environment - be that water in the heyday, or now the atmosphere.

So if your CoViD-19's point of entry happens to be in the olfactory epithelion, it can and probably will spread by cell to cell contact - to those adjacent (para-)hippocampal regions, where the memory loop and part of the motivational functions are located...

...ouch.

Even worse, inside the brain the immune system has to "hold its fire". The more powerful immune responses are somewhat throttled down there. So once the virus is inside, and the brain is infected, it's given even more time to do its damage.

 

[Fra]

This is indeed very interesting. Having managed to stay clean from Covid for a long time, a coupe of month ago I got and had mild symptoms: mild fever, mild upper respiratory symptoms, and since the first day of feber a constant feeling of pressure/numbness in the head. I also after a few days totally lost olfactory sensations, I literally stuffed a cinnamon up my nose and felt nothing. Scary. The smell came back aftre around 5 weeks though.

And for up to week 8/9 I had residual intermittent mild feber, come and go. It often correlated with intermittent more pungent headache, triggered by too much brain engagement, like getting arouse in problem solving or a phonecall. I am the type of person that in the past typically NEVER have headache when ordinarily sick. So this was remarkable, as getting heaache is NOT normal for me, even if I have the flu! In between the pungent headache there was 24/7 a feeling of pressure and numbness in the head. Along with it a sensation of restlessness and increased sensitivy for stressors, and reduce capability for multitasking. There were no single thing I couldn't do, but just one thing at a time. What finally made it go away was one week on constant NSAD and painkillers. After that I seem effectively recovered.

So my subjective impression from analysing myself, is that certainly some sort of inflammatory response somewhere, correlating with headache seems to have been in play. This is indicated also by my fever. I had NO other reason for the feber, not throat issues, not coughig or snoring etc.

So after 8 weeks, I feel fully recovered, but the dynamics the the infection with the oscillatory fever intrigued me. The oscillations seemed to correlate more with cognitive load and psychlogical stressoers, not so much with physical activity. I'm not sure how clever the body is, but I find that transiently the fever has protective effects, but constant high fever puts load on the body. Ideal is to get it to fluctuate, to benefit from the transient response but keep the long term effects low.

Moderate Fever Cycles as a Potential Mechanism to Protect the Respiratory System in COVID-19 Patients​

https://www.frontiersin.org/articles/10.3389/fmed.2020.564170/full

But this is more advice to treatment, than a likely autoregulatory mechanism I guess.

/Fredrik

 

[Oldman too]

Updated info, 04/15
https://www.science.org/content/article/here-s-what-we-know-about-covid-19-s-impact-brain

What at first seemed like a laundry list of neurological symptoms has now been focused into major categories, says Serena Spudich, a neurologist at Yale University. Watch to learn how researchers and doctors have been teasing apart how COVID-19 effects the brain, and testing treatments to alleviate symptoms.