Researchers Report Unexpected Persistence of COVID-19 Vaccine Components in Blood and Tissues Months After Shots
Nikhil Prasad Fact checked by:Thailand Medical News Team Feb 12, 2026 1 hour, 48 minutes ago
Medical News: A new systematic review has raised fresh scientific questions about how long components of COVID-19 mRNA vaccines may remain inside the human body. The study, conducted by researchers from multiple institutions including the Institute for Medical and Health Sciences (IMA Health) in the United States, the University of Guelph in Canada, and United Memorial Medical Center in Houston, Texas, examined published evidence on the persistence of vaccine-derived materials after injection.
Spike protein and modified mRNA from COVID-19 vaccines detected in blood and tissues months after vaccination
In this
Medical News report, we break down what the researchers found, what it could mean, and why it matters.
Early Assumptions About Rapid Clearance
When the Pfizer-BioNTech (BNT162b2) and Moderna (mRNA-1273) vaccines were first introduced, health authorities explained that the modified messenger RNA (mRNA) would quickly break down in the body. Because natural RNA molecules are fragile and degrade rapidly, it was widely assumed the vaccine’s genetic instructions would behave the same way.
However, the review found that real-world studies conducted after mass vaccination campaigns began reporting something different. Several independent investigations detected fragments of vaccine mRNA, spike protein, and lipid nanoparticles in blood and certain tissues weeks or even months after vaccination.
What the Review Examined
The researchers followed internationally recognized PRISMA guidelines for systematic reviews. They searched medical databases for studies that tested bodily fluids and tissues for the presence of vaccine-related components.
The review focused on 16 different bodily fluids, including plasma, saliva, breast milk, urine, cerebrospinal fluid, and others. It also included studies examining lymph nodes and additional tissues. Only studies that used laboratory methods capable of detecting spike protein, modified mRNA, or lipid nanoparticles were included.
Importantly, the review excluded studies where spike protein detection was clearly linked to active COVID-19 infection rather than vaccination.
Key Findings on Persistence
One of the most notable findings was that vaccine-derived spike protein and mRNA were detected beyond the timeframes originally expected. In some studies, spike protein was found in blood samples up to 24 days after vaccination. In others, fragments of spike protein were identified in certain immune cells more than 100 days later, with some cases extending beyond 200 days.
Modified mRNA was also detected in lymph nodes up to 30 days after vaccination in certain individuals. Researchers pointed out that the lipid nanoparticles used to deliver the mRNA may play a role in protecting the genetic material from rapid degradation.
Possible Biological Explanations
The authors discus
sed several potential mechanisms that might explain this persistence. One factor is the chemical modification of the mRNA itself. COVID-19 vaccines use nucleoside-modified mRNA, which is designed to be more stable and less inflammatory than unmodified RNA. Laboratory data prior to 2020 had shown that such modified RNA decays more slowly than natural RNA.
Another possibility is that lipid nanoparticles may accumulate in certain tissues and release their contents over time. There is also discussion about whether stable complexes could form within tissues, acting as temporary reservoirs.
The review emphasized that distinguishing true biological persistence from laboratory detection artifacts remains essential. Some assays are extremely sensitive and may detect very small fragments that do not necessarily indicate active protein production.
Why This Matters
The researchers stressed that understanding how long vaccine components remain detectable is important for improving future mRNA-based therapies. mRNA technology is now being explored for cancer treatments and other infectious diseases. Accurate knowledge of biodistribution and clearance patterns will help refine dosing, design, and safety monitoring.
The clinical significance of prolonged presence remains unclear.
Conclusion
The review highlights a phenomenon that was not fully anticipated during early vaccine rollouts. While the presence of vaccine-derived materials for extended periods does not in itself prove danger, it does underscore the need for deeper investigation. Transparent research into biodistribution, decay kinetics, and long-term biological behavior will be essential not only for public confidence but also for the safe advancement of next-generation mRNA therapeutics. Careful scientific scrutiny, rather than speculation, should guide the next phase of research.
The study findings were published in the peer reviewed journal: Future Journal of Pharmaceutical Sciences.
https://link.springer.com/article/10.1186/s43094-026-00939-2
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