Thread by @ZdenekVrozina

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.

The study followed 228 children (ages 1–18) with PCR-confirmed COVID-19 in Kazakhstan.
Follow-up occurred 24-36 months after infection (2023-2024).
There was also a matched control group of 172 children with respiratory symptoms but no COVID-19.

Long-term findings:
35% of children had heart rhythm abnormalities (sic!)
Shortened PQ
Prolonged QT
Extrasystoles
AV block (1st degree)
Sinus tachycardia
These are not subtle changes - and they’re objectively measurable.

The most affected were adolescents (ages 12–18), who often reported:
Fatigue
Chest pain
Low exercise tolerance
And a non-dipping blood pressure profile - meaning their blood pressure didn’t drop at night like it should.
Among 16–18 year olds, 83% had this pattern (sic!)
In
Non-dipping is a known risk factor for future hypertension and cardiovascular disease.

Antibody tests revealed something else:
IgG levels (immune response markers) were still dramatically elevated up to 3 years post-infection.
Adolescents averaged 480 g/L
Normal range in healthy kids: 14 g/L
This could signal persistent immune activation - or viral antigen persistence. Both are concerning.

Eechocardiograms found structural changes in some kids:
Mitral valve prolapse
Mild regurgitation
Left ventricular enlargement
These changes were not always symptomatic - but they matter.

Blood tests for pro-BNP (a heart stress marker) were normal for most, but elevated in a few children, even without symptoms (sic)
That might suggest early or subclinical cardiac strain - invisible to the naked eye.

Bottom line:
Even mild COVID can leave behind permanent changes in children’s cardiovascular systems.
These effects are measurable and in some cases functionally relevant, especially in teenagers.

And here’s the key point:
These weren’t rare findings.
1 in 3 children had ECG abnormalities
Most adolescents had non-dipping blood pressure
Nearly all had elevated IgG years after infection
This is not anecdotal. This is population-level impact.

Conclusion:
The idea that COVID is no big deal for kids simply doesn’t hold up anymore.
Even when acute illness is mild, the long-term effects on the heart, blood pressure, and immune system should not be ignored.
Children deserve transparency. And follow-up care.

A widespread biological imprint that public health has largely ignored.

Kim et al. (2025). Clinical and Functional Characteristics of Cardiovascular System in Children Who Have Undergone COVID-19. Int Cardiovasc Res J. brieflands.com/articles/ircrj…

/We’re still underestimating SARS-CoV-2’s capacity to cause chronic physiological change.
Just because COVID is common doesn’t mean it’s harmless - especially after repeat exposures.
Think in terms of dose + duration + immune history.

Parallels between HIV and SARS-CoV-2?
It’s not about the viruses being the same.
It’s about how both can leave behind persistent, measurable damage - especially to the immune and cardiovascular systems, even without severe acute illness.

Both HIV and SARS-CoV-2 are RNA viruses with profound effects on the host immune system.
But unlike short-lived respiratory viruses, they leave long-lasting biological imprints.
Even after mild COVID, we now see:
Cardiac changes
Autonomic dysfunction
Persistent immune activation

Non-dipping blood pressure - seen in 83% of adolescents post-COVID - is also common in HIV patients, and linked to autonomic dysfunction.
It reflects disrupted circadian control of vascular tone, with long-term implications.

Chronic IgG elevation (anti-spike) post-COVID resembles immune overactivation seen in HIV.
This suggests:
Delayed immune resolution
Potential antigen persistence
Risk of immune exhaustion
None of this is just a cold behavior.

Both viruses can trigger neuroimmune dysregulation.
HIV: cognitive impairment, autonomic dysfunction
SARS-CoV-2: POTS, fatigue, brain fog, ME/CFS-like profiles
In both cases, immunologic low-grade dysfunction drives chronic symptoms.

Mitochondrial dysfunction is a shared feature:
HIV affects mitochondrial DNA and function in immune cells.
SARS-CoV-2 has been shown to cause respiratory chain disruption in monocytes, heart, and brain cells - even after recovery.

And when it comes to children, these lessons are urgent.
Because unlike with HIV, we’re letting this virus spread freely in pediatric populations, often without long-term monitoring or support.
Children deserve better than wait and see.