The Centers for Disease Control and Prevention (CDC) has long claimed that mRNA from COVID-19 vaccines is “broken down within a few days after vaccination and doesn’t last long in the body.” Yet another study has found that spike protein may circulate in the body more than a year after receiving a COVID-19 vaccine.
A new peer-reviewed paper published in Immunity, Inflammation and Disease found that young, healthy adults were still producing an immune response consistent with the presence of spike protein more than a year after receiving their third dose of an mRNA COVID-19 vaccine—raising serious questions about the long-term presence of vaccine components in the body and the potential for ongoing immune system activation.
Researchers tracked 84 participants, most in their 20s, over a 14-month period after receiving three doses of an mRNA COVID-19 vaccine, and measured levels of proinflammatory cytokines—small proteins secreted by immune cells to signal the immune system to mount a defense. Elevated cytokine levels are typically associated with infection or immune system stress.
Messenger RNA (mRNA) is a type of genetic instruction that tells the body how to make a specific protein. In this case, the mRNA in COVID-19 vaccines tells the body to make the SARS-CoV-2 spike protein so the immune system can learn to recognize it. The CDC refers to mRNA as “messenger RNA,” whereas regulatory documents and Pfizer refer to the mRNA in COVID-19 vaccines as “modified RNA.”
In this case, participants weren’t sick. They had no known infections and no underlying health conditions. And yet, months after vaccination, their immune systems remained on high alert.
Researchers found persistent and significantly elevated levels of cytokines like interleukin-6 (IL-6), interferon gamma (IFN-γ), and tumor necrosis factor-alpha (TNF-α)—all signs that the body was continuing to respond to something foreign. According to the authors, one possible explanation is that spike protein, which the body produces in response to the vaccine’s mRNA instructions, is still being generated long after it was supposed to stop.
The spike protein is the same protein found on the surface of the SARS-CoV-2 virus. In the case of mRNA vaccines like Pfizer’s and Moderna’s, the body is instructed to make a synthetic version of this spike protein to “teach” the immune system how to recognize and fight the virus. The vaccine’s lipid nanoparticles—tiny fat-like particles used to deliver the mRNA into cells—are also known to be highly inflammatory.
This combination of continuous spike production and an inflammatory delivery system could explain the prolonged immune response, researchers said.
Although the study did not directly detect spike protein in the blood, it strongly suggests its presence due to the type and persistence of the immune response. It also notes that this ongoing stimulation may carry risks of immune dysregulation and inflammation-related health problems—particularly if the spike protein is being expressed in sensitive areas like the brain, heart, or reproductive organs.
The findings add to a growing body of evidence that challenges early claims from vaccine manufacturers and public health agencies that the spike protein—and the mRNA used to create it—would remain in the body only for a short time.
Other Studies Show Persistent Spike Protein Production
This latest study isn’t an outlier. A growing number of peer-reviewed studies have documented the persistence of spike protein—or evidence of its effects—long after vaccination.
In an August 2023 paper in Biomedicines, data show the design of the mRNA COVID-19 vaccines allows uncontrolled biodistribution, durability, and persistent bioavailability of the spike protein inside the body after vaccination.
“The lipid-nanoparticle matrix permits widespread biodistribution of mRNA gene codes to cells in most or all organs” and could potentially damage tissues and cause disease, researchers concluded.
A study published in November 2021 in the Journal of Immunology found exosomes expressing spike protein 14 days after vaccination with mRNA COVID-19 vaccines. A spike protein increase was observed four months following the second vaccine dose and increased following booster doses.
In a January 2023 study published in the Journal of Pathology, Microbiology, and Immunology, researchers found full-length or traces of SARS-CoV-2 spike mRNA in some patient samples up to 28 days after COVID-19 vaccination, indicating prolonged spike protein production.
A study published in March 2022 in Cell found vaccine mRNA in lymph nodes on days 7, 16, and 37 following vaccination, with lower but still appreciable levels at day 60. Immunohistochemical staining for spike antigen in mRNA-vaccinated patient lipid nanoparticles in some individuals showed an abundant amount of spike protein 16 days after the second dose, with spike antigen “still present as late as 60 days post-second dose,” researchers said.
A Pfizer Japanese biodistribution study showed COVID-19 vaccine spike protein can travel from the injection site through the blood and accumulate in organs and tissues, including the spleen, bone marrow, liver, adrenal glands, and ovaries. Vaccine mRNA was present from the day of vaccination and persisted in the bloodstream for weeks after vaccination.
Earlier studies detected spike protein fragments in the blood up to 187 days after vaccination. In individuals suffering from post-vaccination syndrome—a condition marked by fatigue, brain fog, neurological issues, and other symptoms similar to long COVID—spike protein has been detected up to 709 days after their last mRNA dose.
While public health authorities have largely dismissed concerns about long-term spike protein expression, a growing number of independent scientists and researchers have warned that the mRNA platform is not as temporary or inert as originally promised. The authors of the new study called for further investigation into the long-term consequences of chronic immune stimulation, particularly in low-risk populations like healthy young adults, who were among the last to be recommended for the shot.
As evidence continues to accumulate, critics argue it’s time for health authorities and vaccine manufacturers to revisit safety claims made under emergency authorization. If the spike protein isn’t going away, they say, neither should the questions.
