Two Yale preprints (Krumholz, Iwasaki et al.) look at post-vaccination syndrome (PVS).
One compares symptoms of PVS with long COVID.
The other goes deeper - into the immune system, viral reactivation, and even persistent spike protein. 🧵 Study 1 (Aug 2025):
682 people took part (441 long COVID, 241 PVS).
Median age: 46
Majority women (74–80%)
Data came from online surveys (self-reported)
It’s the first large, side-by-side comparison of the two conditions.

COVID-19 and the brain: a new study.
What the study looked at -
Researchers examined autopsies of 13 people who died with COVID-19 vs 23 controls.
Goal: to uncover what exactly happens inside the brain during COVID-19.🧵 The central player - microglia.
Microglia = immune cells of the brain. Normally they protect, repair, and keep things in balance.
In COVID-19, they flip - from guardians to drivers of damage.
The worst effects were seen in the medulla oblongata - the brainstem region that controls breathing and circulation.

Not just injections. Mucosal vaccines once promised better protection against transmission of COVID-19.
Today? Only two made it to phase III - and both are outside the West.🧵 Wantai (China) - intranasal vaccine dNS1-RBD (Pneucolin)
First mucosal vaccine to reach phase III
Tested in multi-country trials
Result: Emergency approval in China (2022)

The title says it all:
“Expert consensus on combination antiviral therapy for high-risk COVID-19 patients: A timely call to action”
Translation: China experts are calling for a new HIV-inspired consensus.🧵

https://twitter.com/atranscendedman/status/1959973099513729040

China already has an official consensus (2024) on oral antivirals.
But it focuses on monotherapy - one drug at a time.
That’s not enough for high-risk patients.

A new preprint study shatters the idea that pediatric long COVID is just a mild or different version of the adult form.
It shows that children share the same core immune patterns - and, strikingly, some resemble those seen in chronic infections like HIV.🧵 The paper message is clear - pediatric LC is biologically defined immune dysfunction.

Children display
shifts in monocytes (↑ non-classical, ↓ CCR6),
T cell changes (↑ Tregs, ↓ central memory CD4, exhausted CD8),
exhausted B cells.

How COVID-19 Might Be Accelerating HPV-Related Cancer - with lessons from HIV🧵 COVID-19 isn’t just a lung infection. A new study of over 1.2 million women found something alarming - women who had COVID later developed more HPV-linked cancers. Cervical cancer risk up 67%, anal 92%, vulvar 98%, oropharyngeal 78%.

Why do men with severe COVID-19 often show low testosterone and cholesterol? For years, we knew ACE2 was abundant in testicular tissue.
Now we have direct evidence - SARS-CoV-2 hijacks Leydig cells, diverting cholesterol away from hormones and into viral particles.🧵 For the first time, SARS-CoV-2 particles were found inside lipid inclusions and organelles of Leydig cells - the testicular cells that produce testosterone.
This discovery helps explain why men with severe COVID-19 often show low testosterone and cholesterol.

COVID-19 leaves DNA scars.
A new study in BMC Infectious Diseases shows COVID-19 can leave lasting DNA damage in immune cells - even weeks after infection.
Here’s what the researchers actually found🧵

https://twitter.com/harryspoelstra/status/1958118806401814950

Researchers took white blood cells from
patients with mild COVID,
hospitalized patients with severe COVID (some ICU),
and healthy controls.

COVID-19 accelerates vascular aging - and the damage may not fully heal.
New data from the CARTESIAN study shows measurable increases in arterial stiffness after COVID - especially in women.
But there's more to the story🧵 COVID-19 speeds up vascular aging - increasing arterial stiffness, measured by pulse wave velocity (PWV).
This effect shows up even after mild infections, hits women harder, and is only partially reversible.

A new study finds that immune cells from long COVID patients operate in a metabolically inefficient mode.
Mitochondria are producing and breaking down ATP at the same time.
This might help explain persistent fatigue and reduced physical capacity.🧵 Researchers analysed peripheral blood mononuclear cells (PBMCs) from long COVID patients (n=27) and healthy controls (n=16).
They measured
oxygen consumption (OCR)
mitochondrial membrane potential
ATP synthase activity
mitochondrial DNA and biomass

Two 2025 studies confirm it:
In some people, COVID leaves parts of the brain functionally switched off.
PET and EEG both show disruptions in regions that control attention, motivation, and emotion.
What that actually means🧵 Reduced glucose metabolism = less energy in certain parts of the brain, measured with PET using radioactive glucose. Siqueira et al., 2025.
Most affected: the left orbitofrontal cortex (just above the eyes), often extending into the frontal lobe.

More than 2 years after infection, people with Long COVID still show signs of a leaky blood-brain barrier (BBB) - the brain’s protective filter.
A new MRI study links this persistent leakiness to motor dysfunction. Here’s what that means🧵 The BBB acts like a security checkpoint for the brain.
It keeps out toxins, viruses, immune cells - anything that could harm sensitive brain tissue.
When the barrier breaks down, the brain becomes exposed to inflammation, immune attacks, and possibly long-term damage.

Metformin cut the risk of long COVID.
A randomized, placebo-controlled trial tested a short course of metformin given during acute COVID.
While the primary endpoint didn’t reach the pre-specified threshold, some secondary outcomes were striking🧵

https://twitter.com/atranscendedman/status/1955651958397862231

Doctor-diagnosed long COVID at day 180:
Metformin: 0.56%
Placebo: 1.17%
Absolute reduction: -0.61 percentage points
Relative risk reduction: 50%
PPE: 0.96 (just below the 0.975 threshold)

COVID-19 in early childhood disrupts the gut microbiome - even without symptoms - and may dampen key immune pathways. A new study sheds light on this underappreciated risk. Let’s break it down🧵 Researchers studied children under 2 years old with mild COVID-19.
No GI symptoms!
Still, their gut microbiome looked very different from healthy peers.
Less diversity
Loss of protective bacteria
Rise in opportunistic bugs
Predicted suppression of immune-related pathways

A big US study (HEROS, 1156 people, May 2020-Feb 2021) found something surprising.
If you had a rhinovirus (common cold) in the past month, your chance of catching COVID was 48% lower.
If you still got it, your viral load was almost 10× lower.🧵 Why?
Rhinovirus flips on a powerful interferon alarm in your airway cells.
Result - 24 antiviral genes (RIG-I, MDA5, IFIT1…) are primed and ready to slow down other viruses - including SARS-CoV-2.

Long COVID & viral persistence - new evidence
A new study detected a peptide fragment specific to SARS-CoV-2 nsp3 in blood extracellular vesicles (EVs) from Long COVID patients - months to years after infection.
Let’s unpack why this matters.🧵 EVs are tiny membrane packages released by cells, carrying proteins, RNA, and lipids.
They can travel in blood, cross biological barriers, and deliver their contents to other cells - bypassing normal immune surveillance!

Even without live virus, blood serum can carry signals powerful enough to change how healthy tissue works.
A new peer-reviewed study shows serum from ME/CFS and long COVID patients can directly impair muscle function in lab-grown human muscle.
5 years in, we still don’t know exactly which factors are responsible 🧵 The team built sophisticated 3D mini-muscles from human myoblasts. These bioengineered tissues contract when electrically stimulated, much like real muscles.
Then they bathed them in serum from ME/CFS or long COVID patients and watched what happened.
The results were striking.

Post-COVID pulmonary fibrosis (PC19-PF) = permanent scarring of lung tissue after SARS-CoV-2 infection.
Not just leftover inflammation - it’s a distinct biological state.
Some patients improve on their own. Others? The scarring progresses. Detecting it early is critical. Review🧵 How common? Depends who you look at
Hospitalized patients: 30-40% show PF signs at 6-12 months.
General population: lower, but true numbers are unknown.
Research bias alert: the sickest patients are followed most closely, so mild cases are often missed.

Cardio-Pulmonary Features of Long COVID review.
From molecular pathways to clinical impact - and why heart and lung damage often go hand-in-hand.
Most mechanisms are variant-agnostic; prevalence numbers reflect the specific wave & vaccine context.🧵 Early imaging data was alarming.
In a JAMA Cardiology 2020 study (Wuhan strain, early 2020, pre-vaccine):
78% of recently recovered patients showed cardiac abnormalities on MRI
60% had signs of ongoing myocardial inflammation
These were not only patients with severe acute illness - many had mild initial COVID.

New research reveals that #COVID19 can quietly damage blood vessels and disrupt red blood cell production - even in people with absolutely no symptoms. This was uncovered using a tool called an epigenetic liquid biopsy, which tracks where tiny fragments of DNA in your blood originate.🧵 Epigenetic liquid biopsy - from a small blood sample, scientists can read the DNA fragments released by dying cells and tell which tissues they came from - and even what genes were active before the cells died.
A powerful way to spot hidden damage early.

Can COVID-19 cause lasting heart changes in children - even after a mild case?
Yes.
A new peer-reviewed study followed kids after infection.
The shocking part? Just how many still show signs of heart dysfunction years later.🧵

https://twitter.com/harryspoelstra/status/1952681591915876393

Even in children who had mild COVID, researchers found measurable - and persistent changes in heart function and blood pressure.
These weren’t isolated cases.
Some of the effects were detectable years after infection.