A new preprint study, published on February 18, 2025, on medRxiv, explores potential immune system changes in individuals reporting chronic illness after receiving a COVID-19 vaccine. While vaccines have been a crucial tool in reducing COVID-19 deaths, a small subset of people have described lingering, debilitating symptoms—sometimes referred to as post-vaccination syndrome (PVS).
What the Study Found
Researchers at Yale University conducted a case-control study involving 42 people with PVS and 22 healthy, vaccinated controls. They found distinct immune system differences in those with PVS, including:
- Altered T Cell Profiles: Reduced memory CD4 T cells and increased TNFα-producing CD8 T cells, which could indicate persistent inflammation.
- Lower Antibody Levels: Individuals with PVS had lower anti-spike antibodies, likely because they received fewer vaccine doses compared to controls.
- Epstein-Barr Virus (EBV) Reactivation: PVS participants showed higher rates of recent EBV activity, which has also been linked to long COVID.
- Persistent Spike Protein in Blood: Some PVS patients still had circulating spike protein (a key part of the COVID-19 virus and vaccines) up to 709 days after their last vaccine dose.
What It Means
The study suggests that in rare cases, some individuals may experience long-term immune system changes after vaccination. However, researchers stress that vaccines remain overwhelmingly beneficial, preventing millions of COVID-19 deaths. The findings highlight the need for further studies to understand PVS and explore possible diagnostic tools or treatments.
Important Caveats
This research is a preprint, meaning it has not yet undergone peer review. It should not be used to guide medical decisions, and its findings require further validation.
Research Study Source
Bhattacharjee, B., Lu, P., Monteiro, V. S., Tabachnikova, A., Wang, K., et al. (February 18, 2025). Immunological and antigenic signatures associated with chronic illnesses after COVID-19 vaccination. medRxiv. https://doi.org/10.1101/2025.02.18.25322379
