Researchers Warn Platelet Concentrates from COVID-19 Recovered Blood Donors May Be Unsafe for Medical Use
Nikhil Prasad Fact checked by:Thailand Medical News Team Jun 02, 2025 2 weeks, 2 days, 17 hours, 41 minutes ago
Medical News: Concerns Rise Over the Safety of Blood Products from Recently Recovered COVID-19 Donors
New research from the Blood Transfusion Research Center at the High Institute for Research and Education in Transfusion Medicine in Tehran, Iran, has raised important safety concerns about the use of platelet concentrates (PCs) collected from individuals who recently recovered from COVID-19. The findings suggest that certain blood components may not be functionally suitable for medical use if collected too soon after recovery from the virus.
Researchers Warn Platelet Concentrates from COVID-19 Recovered Blood Donors May Be Unsafe
for Medical Use
Japanese scientists have already raised concerns about using blood from individuals who received COVID-19 mRNA vaccines for medical transfusions.
https://www.thailandmedical.news/news/breaking-japanese-researchers-warn-about-risks-associated-with-blood-transfusions-from-covid-19-mrna-vaccinated-individuals
This new study is likely to further complicate matters for blood banks, making it increasingly difficult to secure safe and suitable blood supplies for various medical procedures. The challenge is exacerbated by the fact that a significant portion of the global population has been vaccinated, and highly transmissible SARS-CoV-2 variants continue to spread rapidly across multiple regions worldwide.
While COVID-19 has long been known to affect clotting and blood components, this
Medical News report brings attention to a less discussed but critical issue: whether platelets from donors who have recovered from the virus can safely be used in transfusions. Platelet transfusions are vital in many medical situations, especially in patients with severe bleeding, cancer, or those undergoing surgeries. However, this new study shows that the platelet function in COVID-recovered donors may be impaired in subtle but serious ways.
Study Details and Groups Compared
The study involved two groups of male blood donors aged between 30 and 40. One group had recovered from COVID-19 between 1 to 3 months before donation (the “case group”), while the second group had recovered more than 6 months earlier (the “control group”). The timing was important because the 1–3 month period after recovery is known to be a phase of immune system instability, with lingering inflammation and oxidative stress that may continue to impact the body—even after symptoms have subsided.
Researchers focused on evaluating several key biochemical and functional parameters of platelet concentrates from both groups during a 5-day storage period, which is the typical shelf life for transfusion platelets. They examined factors such as glucose and pH levels, lactate production, enzyme activity (LDH), oxidative stress (ROS), nitric oxide levels, and crucially, platelet aggregation—an impor
tant measure of how well platelets can form clots when needed.
Key Findings: Platelet Aggregation Impairment
One of the most striking discoveries was a significant impairment in platelet function in the case group. Platelet aggregation was assessed using two types of chemical triggers: collagen and arachidonic acid. These substances normally cause healthy platelets to clump together.
In both groups, collagen-induced aggregation declined during storage, but the decline was especially sharp in those who had recently recovered from COVID-19. However, the most alarming result came with arachidonic acid: in the case group, aggregation response dropped significantly over time, while the control group maintained stable function.
This selective impairment suggests that SARS-CoV-2 infection may leave lingering effects on the arachidonic acid pathways within platelets—an important pathway that influences how platelets respond to injuries and form clots.
Biochemical Changes Were Similar—but Function Tells a Different Story
Although glucose, pH, and lactate levels changed similarly in both groups during storage—indicating typical metabolic degradation—functional differences remained. Mean platelet volume (MPV), a marker often associated with platelet activation, rose in both groups. ROS levels also increased over time in both groups, suggesting rising oxidative stress. Still, the ability of platelets from recent COVID-19 donors to respond effectively was notably diminished, despite having “normal” biochemical profiles.
This disconnect between appearance and function is particularly concerning because current blood screening protocols do not assess platelet function in this way. This means that PCs could appear acceptable based on standard tests but may perform poorly or even dangerously in clinical scenarios.
Implications for Blood Transfusion Safety
These findings raise red flags about relying on platelet concentrates from individuals who have recently recovered from COVID-19, even if they have passed standard donation eligibility screenings. COVID-19 may continue to subtly affect platelet functionality long after recovery, especially within the first few months.
While current blood donation policies in many countries, including Iran, recommend a deferral period of 14 to 28 days post-recovery, this study suggests that a longer deferral time—possibly exceeding 3 months—might be necessary to ensure transfusion safety. More extensive clinical trials and studies are needed to verify whether transfusions from these PCs could lead to complications in recipients.
Conclusions and Call for Caution
The study concludes that although basic biochemical markers in platelet concentrates from recently recovered COVID-19 donors appear largely normal, there is a clear, selective deterioration in functional platelet aggregation—especially involving the arachidonic acid pathway. This may reflect lingering effects of COVID-19 on the donor's immune and hematological systems.
These impaired platelet functions could potentially increase the risk of transfusion failure or clotting disorders in vulnerable patients. While further research is needed, hospitals and blood banks should exercise caution and consider extending the waiting period before accepting donations from COVID-19-recovered individuals.
Blood services worldwide may need to revisit their donor screening policies to reflect these findings and reduce any possible risks associated with using platelet concentrates from recently recovered COVID-19 patients. Ensuring the functional quality of transfused platelets is just as critical as their basic biochemical properties.
The study findings were published in the peer reviewed Journal of Clinical Laboratory Analysis.
https://onlinelibrary.wiley.com/doi/10.1002/jcla.70062
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