Alarming Discovery That Asymptomatic COVID-19 Infections Causes Hidden Blood Vessel and Red Blood Cell Changes
Nikhil Prasad Fact checked by:Thailand Medical News Team Aug 08, 2025 2 hours, 47 minutes ago
Medical News: A Groundbreaking Study on COVID-19’s Silent Damage
A team of researchers from the Hebrew University of Jerusalem, Shaare Zedek Medical Center, Hadassah Medical Center, and GRAIL LLC has uncovered shocking evidence that even people who show no symptoms of COVID-19 can still suffer hidden damage to their blood vessels and red blood cells. Using advanced “epigenetic liquid biopsy” techniques, the scientists found that SARS-CoV-2 infection, regardless of severity, triggers subtle but measurable changes in the body that could have long-term health consequences. This
Medical News report highlights how these findings could reshape our understanding of so-called “mild” or “asymptomatic” cases.
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Alarming Discovery That Asymptomatic COVID-19 Infections Causes Hidden Blood Vessel and Red Blood Cell Changes
Looking Beyond Obvious Symptoms
For years, COVID-19 research focused largely on patients with severe symptoms, especially those in hospitals. But in this new study, scientists analyzed the DNA fragments floating in the bloodstream—cell-free DNA (cfDNA)—to see which tissues in the body were shedding cells. These DNA fragments carry chemical “tags” that reveal their origin, allowing doctors to see which tissues have been damaged or are regenerating. Astonishingly, asymptomatic patients still had elevated cfDNA from blood vessel lining cells (endothelial cells) and immature red blood cells (erythroblasts), even though they appeared perfectly healthy on the surface.
What the Study Found
In severe COVID-19 cases, researchers observed massive cfDNA release from the lungs, heart, blood vessels, and immune cells—clear evidence of widespread tissue damage. But in people with no symptoms, there were no signs of lung or heart damage. Instead, these “healthy” carriers still showed increased turnover of vascular endothelial cells and red blood cell precursors. This suggests that even without illness, the virus may cause hidden injury to blood vessels and disrupt the normal production of red blood cells.
The elevated vascular endothelial cfDNA may indicate that blood vessels are being damaged at a microscopic level, prompting the body to replace these cells more quickly. Similarly, the increase in erythroblast cfDNA points to accelerated red blood cell production—possibly to replace cells damaged by the infection.
Why This Matters
Blood vessel health is crucial for the entire body, affecting heart function, brain health, and circulation. Even minor, symptom-free vascular damage could contribute to future problems, including the risk of blood clots or persistent fatigue. The researchers warn that these invisible changes might help explain why some people develop “long COVID” weeks or months after an apparently harmless infection.
How the Research Was Done
The team used deep whole-genome bisulfite sequencing and targe
ted DNA methylation markers to identify the source of cfDNA in blood samples from 120 hospitalized patients, 19 asymptomatic patients, and 68 healthy controls. They also examined chemical modifications on chromatin—the packaging of DNA inside cells—to detect immune responses that occurred before the cells died. Both severe and asymptomatic patients showed signs of interferon-related immune activity, revealing that the immune system was actively responding even when no illness was felt.
The Bigger Picture
These findings challenge the belief that an asymptomatic COVID-19 infection is entirely harmless. The hidden vascular and blood cell changes observed could be part of a broader pattern of “silent” damage that accumulates over time, raising questions about potential long-term effects on population health. The researchers suggest that such changes could be used as biomarkers to predict which patients are at risk for later complications, even if they initially feel fine.
The implications extend beyond COVID-19, as epigenetic liquid biopsy technology could help detect subtle organ damage in many other diseases without invasive tests. However, more research is needed to determine how long these cellular changes persist and whether they directly lead to chronic health problems.
The study findings were published in the peer reviewed journal: Life Science Alliance
https://www.life-science-alliance.org/content/8/10/e202503417
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Read Also:
https://www.thailandmedical.news/news/even-mild-or-asymptomatic-covid-19-infections-leave-over-700-dna-methylation-changes-after-recovery
https://www.thailandmedical.news/news/study-warns-silent-spread-of-covid-19-is-more-extensive-than-thought-driven-by-asymptomatic-infections
https://www.thailandmedical.news/news/post-mild-or-asymptomatic-covid-19-infections-still-exhibit-ongoing-neuron-and-astrocyte-injury-even-at-10-months-follow-up
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