Adenoviral Vaccines Including Adenovirus-Based COVID-19 Vaccines Are Linked to Red Blood Cell Damage and Clot Risks!
Nikhil Prasad Fact checked by:Thailand Medical News Team Nov 30, 2025 1 hour, 21 minutes ago
Medical News: A surprising discovery about red blood cells
Scientists from Hanyang University, Chungnam National University, and Ewha Womans University in South Korea have uncovered new clues about how adenoviral vectors—the same technology used in several COVID-19 vaccines—may trigger changes in red blood cells that contribute to unusual venous blood clots. Although claims of adenoviral vaccines helping to protect millions worldwide have been made, researchers say the rare clotting events seen during the pandemic may involve more than platelets alone, and their new findings provide a fresh layer of understanding. According to this
Medical News report, the study focused on how these adenoviral vectors behave when they directly interact with circulating red blood cells.
New research reveals how adenoviral vectors can reshape red blood cells and intensify clot formation
Why red blood cells matter in blood clots
While platelets usually receive all the attention in discussions about clotting, red blood cells also help determine how clots form, especially in low-flow veins. In carefully controlled rat experiments, the Korean research team used a modified adenovirus known as Ad5 vector-rAd/HA(PR8) to observe what happens when red blood cells encounter viral particles at levels similar to those used in existing adenoviral vaccines.
Key findings reveal a chain reaction inside the bloodstream
The study showed that even under conditions where less than ten percent of red blood cells were damaged, the viral exposure caused dramatic structural and biochemical changes. Red blood cells began exposing a molecule called phosphatidylserine on their surface, which acts as a powerful accelerator for clot formation. Using scanning electron microscope images, the researchers documented cells shifting from healthy biconcave discs into spiky echinocytes and eventually into rigid spherocytes. These shapes are known to support clot formation by offering more procoagulant surfaces.
The team also measured a sharp rise in microvesicles—tiny fragments shed from stressed or reshaped red blood cells. These microvesicles carry additional pro-clotting signals. Blood samples taken just four hours after exposure showed a clear dose-dependent increase in thrombin, one of the body’s main clot-producing enzymes. In live animal tests, clots forming in the inferior vena cava were significantly larger when adenoviral vectors were present, confirming that these red blood cell changes translate into real-world clotting effects.
A broader scientific message for future vaccine design
These findings do not challenge the life-saving impact of adenoviral vaccines, but they highlight the need to include red blood cell biology in future safety assessments. The research suggests that structural stress, phosphatidylserine exposure, and micro-vesicle release can combine to amplify clotting in veins.
Understanding these early effects could help scientists design improve
d vectors that avoid triggering such responses and prevent rare clotting complications across different viral platforms. These insights may also reshape how preclinical testing evaluates clotting risks, ensuring more complete screening of blood-related effects.
The study findings were published in the peer reviewed: International Journal of Molecular Sciences.
https://www.mdpi.com/1422-0067/26/23/11606
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Read Also:
https://www.thailandmedical.news/news/breaking-covid-19-vaccine-exclusive-possible-dangers-of-using-adeno-associated-virus-aav-vectors-for-covid-19-vaccines-
https://www.thailandmedical.news/news/german-researchers-say-johnson-and-johnson-s-and-astrazeneca-s-covid-19-vaccine-blood-clots-are-due-to-adenovirus-vector-issues-and-can-be-fixed
https://www.thailandmedical.news/articles/vaccine-news
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