A team of researchers at Yale University has made early discoveries about a rare condition affecting a small number of individuals following COVID vaccination.
This condition, which they have termed post-vaccination syndrome (PVS), appears to cause chronic health issues that persist for months or even years.
While most people experience no lasting effects from the COVID vaccine, a fraction develop persistent symptoms such as fatigue, brain fog, dizziness, and exercise intolerance.
These symptoms often emerge within a day or two of vaccination and may progressively worsen over time.
Uncovering Immunological Patterns in PVS
In their preliminary findings, the Yale team identified unique immunological markers in individuals suffering from PVS.
The researchers hope that these discoveries will pave the way for better diagnostic tools and potential treatments.
“This work is still in its early stages, and we need to validate these findings,” said Akiko Iwasaki, Sterling Professor of Immunobiology at Yale School of Medicine.
“But this is giving us some hope that there may be something that we can use for diagnosis and treatment of PVS down the road.”
A professor of cardiology at Yale School of Medicine, Harlan Krumholz, emphasized the importance of listening to affected individuals and conducting rigorous research.
“It’s clear that some individuals are experiencing significant challenges after vaccination. Our responsibility as scientists and clinicians is to listen to their experiences, rigorously investigate the underlying causes, and seek ways to help,” he stated.
Key Findings from the Study
The researchers examined blood samples from 42 people with PVS and 22 individuals without symptoms. Their analysis revealed that those affected by PVS had lower levels of two types of white blood cells.
Additionally, people with PVS who had never contracted COVID showed reduced levels of antibodies against the SARS-CoV-2 spike protein, likely because they received fewer vaccine doses.
“Fewer vaccine doses and no viral infection means the body’s immune system has had little opportunity to develop a defense to the virus,” the researchers explained.
Interestingly, some individuals with PVS also had higher levels of the SARS-CoV-2 spike protein in their blood. This spike protein enables the virus to infect human cells and has also been linked to a greater risk of developing long COVID.
However, not all PVS patients had detectable spike proteins, leading researchers to believe that multiple mechanisms may be responsible for the condition.
“We don’t know if the level of spike protein is causing the chronic symptoms, because there were other participants with PVS who didn’t have any measurable spike protein — but it could be one mechanism underlying this syndrome,” said Iwasaki.
Possible Risk Factors for PVS
Beyond spike protein presence, other factors may contribute to post-vaccination syndrome.
Researchers highlighted autoimmunity, tissue damage, and reactivation of Epstein-Barr virus (EBV) as potential triggers.
A clinical professor of medicine at NYU Langone Health, Dr. Marc Siegel, confirmed that PVS is a known phenomenon seen with many vaccines, not just COVID.
“Post-vaccination syndrome is real, and has been found [to occur] from many vaccines,” Siegel stated.
Siegel also noted that elevations in inflammatory immune cells (CD8 and TN alpha) and a decrease in CD4 helper cells, which normally help regulate the immune response, may explain the prolonged symptoms experienced by some individuals.
The Need for Further Research
Despite these findings, researchers stress that more studies are needed to understand, diagnose, and treat PVS effectively.
“We’re only just starting to make headway in understanding PVS,” said Krumholz. “Every medical intervention carries some risk, and it’s important to acknowledge that adverse events can occur with vaccines.”
He emphasized the importance of compassionate, open-minded research to support those affected.
Siegel echoed this sentiment, adding, “This needs to be further studied in terms of understanding how common prolonged COVID vaccine side effects are and how to predict them and treat them.”
As research progresses, scientists hope to develop targeted treatments to help those suffering from PVS, ensuring that vaccine safety continues to be thoroughly understood.
