COVID-19 Vaccines and Post-Vaccination Syndrome: A Medical Mystery

Back in the summer of 2020, people could hardly wait for COVID-19 vaccines to be developed so that the pandemic would end. Within a few months, though, people were starting to report side effects such as Bell’s palsy or a false-positive result on mammograms. A new study has just revealed a disturbing post-vaccination syndrome (PVS) that persists long after the jab.

What Is Post-Vaccination Syndrome?

Yale researchers have found that some people report lasting fatigue, brain fog, palpitations, insomnia, neuropathy, headache, tinnitus and/or dizziness following a COVID-19 shot (MedRxiv, Feb. 18,2025). If that sounds a lot like long COVID, we would not disagree.

Another very similar long COVID symptom is something doctors have labeled exercise intolerance. People with post-vaccination syndrome also experience utter exhaustion after minor physical activity. It is also called post exertional malaise (PEM). Sometimes just taking a shower or scrounging for lunch can trigger this debilitating syndrome.

Reactivation of Latent Viruses:

One of the most interesting findings in the Yale study is that some people with post-vaccination syndrome experience reactivation of the Epstein-Barr virus. We have been paying close attention to the idea that both the COVID vaccine and COVID-19 may reactivate latent viruses that have been lying dormant in the body for years.

Think about herpes viruses as an example. They can hibernate for years before emerging to cause a cold sore or a shingles attack. We know that stress, sun exposure and other infections can reactivate herpes viruses. Apparently, COVID-19 vaccines may also reactivate Epstein-Barr virus. The researchers, who also study people with long COVID, found that those with PVS  had significantly higher antibodies to Epstein-Barr virus than healthy individuals. This finding and related changes in immune system cells suggests that reactivation may play a role in post-vaccination syndrome.

Post-Vaccination Syndrome and SARS-CoV-2 Spike Protein:

There were other differences between the 42 individuals with PVS and the 22 healthy people in the study. The researchers found a significantly different pattern of autoantibodies.

Oddly, they also found that those with PVS showed elevated levels of the spike protein used to generate an immune response to the virus. Usually, this protein is only detectable in a person’s blood for several days after vaccination. People with symptoms of post-vaccination syndrome had detectable levels of spike protein from 26 to 709 days after the jab. This is a striking finding that will no doubt spur further investigation.

The investigators write:

“Post-acute conditions following COVID-19 vaccination have been reported for multiple vaccine platforms including mRNA and adenoviral-vectored vaccines. We observed that the general
health status of the PVS participants was far below the general US population average based on the GHVAS scores. The patient-reported outcome scores from the PROMIS29 domains were also indicative of lower quality of life. A large fraction of individuals reported the onset of symptoms to be as early as within one day of COVID-19 vaccination.”

This is not the first report to raise some red flags about potential risks of COVID-19 vaccination. A study published last year in the journal Vaccine reveals some interesting side effects of COVID-19 vaccines (Vaccine, Feb. 12, 2024).

What Serious Side Effects Do COVID-19 Vaccines Cause?

This study, called the Global Vaccine Safety Project, included 99 million people from eight countries. Australia, Canada, Argentina, Denmark, Finland, France, New Zealand and Scotland participated. All vaccinated large numbers of people and have good health records for tracking the outcomes.

In general, serious side effects were rare. The researchers predicted how frequently a severe complication might occur based on the rates before the pandemic began. For example, they estimated rates of myocarditis, or inflammation of the heart muscle, in a healthy unvaccinated population. This problem was twice as common following vaccination. Nonetheless, there were relatively few cases.

Guillain Barré syndrome, a neurological complication that causes temporary paralysis, was more common after the AstraZeneca vaccine. The researchers predicted 76 cases of Guillain Barré in healthy unvaccinated people. They actually observed 190 cases. That’s about 2.5 times more than baseline.

Another serious but rare complication was acute disseminated encephalomyelitis following the Moderna vaccination. Scientists expected 2 cases among 10 million people vaccinated. Instead, they reported 7.

In Conclusion:

The conclusion seems to be that COVID vaccines do indeed cause vascular and neurological adverse reactions, but the overall incidence is low. An independent study of COVID-19 vaccines demonstrated that vaccinated individuals have a reduced risk for severe outcomes from the infection, including Long COVID (Vaccines, Feb. 2024).

Final Words About Post-Vaccination Syndrome:

We have observed incredible polarization with respect to politics and public health policy. It pains us that so many people have become less curious and more dogmatic. We have seemingly lost our ability to recognize complexity and nuance, but those are critical when it comes to medications or vaccinations.

Every drug has the potential to cause some side effects for susceptible individuals. The same is true for vaccines. We should not be surprised that there may be complications from the COVID-19 vaccine. That doesn’t mean we should avoid all vaccines. Joe has described in detail what it was like to have polio as a young child at this link.

Please share your own experience with long COVID or post-vaccination syndrome (PVS). If you think this article is worthwhile, please share it with friends and family. Thank you for supporting our work.