Thread by @ZdenekVrozina

SARS-CoV-2 causes long-lasting structural changes in the brain - even in people without symptoms.
Recovered ≠ normal. In this study, every single recovered participant still showed measurable abnormalities.
And this is 6-12 months after infection🧵

https://twitter.com/HarrySpoelstra/status/1994384304214864320

47 participants - Long COVID (19), recovered without symptoms (12), uninfected controls (16)
Multimodal 3T MRI - myelin (T1w/T2w), white matter microstructure (MD/AD/RD/FA), MR spectroscopy
Variant based on timing/location - Australia 2022–23, this was almost certainly Omicron
Headline?
Both post-COVID groups show clear structural brain differences.

Recovered often shows stronger myelin reorganization, while Long COVID shows more metabolic stress and some inflammation related diffusion patterns.

What does stronger myelin reorganization mean?
The T1w/T2w ratio reflects myelin content.
Long COVID - increased myelin signal in a few regions
Recovered - increased myelin signal across much broader areas
Controls - none of these patterns

This doesn’t look like demyelination.
It looks like repair/remyelination/glial activation.
Not necessarily functional

Key point.
Not necessarily functional means the brain may be producing new myelin or glial scaffolding,
but this does not guarantee a return to original signal quality or network efficiency.
Repair ≠ restoration.
Sometimes it’s compensatory wiring - keeps the system running, but less efficiently and at higher metabolic cost.

Long COVID = stronger metabolic and diffusion abnormalities.
Metabolism:
↓ Glutamine (immune and mitochondrial consumption).
↑ NAA (neurons trying to compensate for reduced efficiency).

Diffusion - patterns matching inflammation or tissue densification (MD↓) and rigidity/reorganization (FA↑), especially in SLF - a key pathway for attention and cognition.
LC brains show higher ongoing metabolic strain, slowing or distorting repair.

Recovered = faster, but not guaranteed better repair.
Recovered participants show
less metabolic strain
more extensive myelin remodeling
evidence of large scale reorganization of white matter pathways

This might reflect a faster compensatory repair response, but not necessarily a return to the original architecture.
Two different ways the brain adapts to the same viral insult.

Imaging aligns with symptoms.
More myelin in temporal regions = better physical function
Less myelin in midbrain = worse cognitive performance
Cognitive symptoms are not psychological - they map onto structural and metabolic changes.

Sum:
SARS-CoV-2 disrupts myelin regulation (similar to known neurotropic viruses)
Leaves a measurable footprint months after recovery
Long COVID and recovered follow different repair trajectories
Brain repair can be partial, maladaptive, energetically expensive
These changes persist (for now months after infection)

What this shows.
SARS-CoV-2 has long-term neurobiological effects
Recovered ≠ normal - all recovered showed measurable abnormalities
LC ≠ recovered - different stress patterns, different compensations
Affects networks for attention, cognition, motor control, alertness
Long COVID is a measurable neurological condition, not a functional or psychological syndrome

Thapaliya et al., Altered Brain Tissue Microstructure and Neurochemical Profiles in Long COVID and Recovered COVID-19 Individuals (2025, pre-proof). sciencedirect.com/science/articl…

We’re not saying SARS-CoV-2 is the new HIV etc
But we are saying this -
The mechanisms SARS-CoV-2 uses in the brain overlap with viruses that do produce long-lasting neural changes.

Spike - activates microglia, alters astrocyte metabolism
N protein - drives inflammatory cascades
ORF proteins - disrupt mitochondrial function
Nsp1 - blocks ribosomes, limiting the cell’s ability to produce proteins needed for neuronal repair and myelin maintenance

These mechanisms naturally produce the kinds of MRI patterns we see
glial activation
myelin remodeling
rigid or reorganized white matter pathways
metabolic stress in neurons

These are not random MRI quirks.
These are exactly the changes you’d expect from a virus whose proteins block ribosomes, overload glia, and destabilize neuronal metabolism.
Time is passing - and we still refuse to learn from the biology of viruses (proteins) like HIV.

And one last question we should dare to ask.
What will the brains of children look like if we deliberately leave them without any protection against repeated SARS-CoV-2 infections?

From everything we already know - MRI, EEG, immune markers, neuroinflammation, metabolic profiles, developmental studies - several biologically plausible trajectories are already visible.
Every single one of them points to the same thing - a failure of public health. @szupraha @ZdravkoOnline @adamvojtech86

To be precise - the MRI abnormalities in the recovered group were group-level effects.
With only 12 participants, a result this strong almost certainly reflects a broad signal across the group - even though the design can’t determine each individual.
So instead of “all 12,” the correct interpretation is -
“almost everyone in the recovered group showed measurable differences compared to controls.”