The LISTEN Study

Led by esteemed professors Dr. Harlan Krumholz, a cardiologist, and Dr. Akiko Iwasaki, an immunologist, the LISTEN study examined 241 adults who reported symptoms of post-vaccination syndrome (PVS) following Covid-19 vaccinations between May 2022 and July 2023.

The study's cohort consisted of 55% Pfizer recipients, 37% Moderna recipients, and the remaining 8% received vaccines from AstraZeneca, Johnson & Johnson, or Novavax. The average age was 46 years, predominantly female and White, with at least 34% having a prior Covid-19 infection.

Participants completed extensive surveys about their symptoms, with the time from vaccination to survey completion averaging 595 days (approximately 19.5 months).

Key findings from the survey included:

• Mental Health: In the week before the survey, 98% reported feeling worn out, 93% experienced unease, and many struggled with feelings of anxiety, depression, and hopelessness. Some reported limited social support and feelings of loneliness.
• Physical Symptoms: The average interval from vaccination to the onset of symptoms was 3 days, with an average of 22 reported symptoms. Common issues included exercise intolerance (71%), fatigue (69%), brain fog (63%), and insomnia (61%). A significant 86% indicated that their symptoms disrupted daily activities.

The researchers noted that 36% were diagnosed with anxiety, 33% with neurological issues, and a variety of other conditions. Participants experimented with 209 different treatments, the most frequent being probiotics and vitamins, yet reported a low quality of life despite these efforts.

This research is pivotal, being the largest detailed account of individuals experiencing PVS, suggesting a potential link between vaccination and symptom onset.

Causality and Observational Studies

However, the authors acknowledged the study's limitations, stating that it cannot confirm causality or estimate the incidence and prevalence of PVS. Observational studies like LISTEN cannot establish cause and effect, which is a critical distinction from randomized clinical trials.

The absence of control groups in LISTEN weakens its findings, making it more of a case series rather than a cohort study. Thus, the increased risk of PVS in vaccinated individuals compared to unvaccinated ones cannot be determined.

Broader Context: Confounding Factors

Several confounding factors may have influenced the development of PVS. A significant portion of participants had pre-existing health conditions prior to the pandemic, with 75% reporting at least one comorbidity, including gastrointestinal issues and anxiety. The study authors concluded these conditions did not account for PVS symptoms but lacked explicit testing to support this claim.

Dr. Linda Geng from Stanford University pointed out that symptoms reported could overlap with those of long-Covid, complicating accurate categorization. Moreover, many could have unknowingly contracted Covid-19, further clouding the results.

Chronic fatigue was prevalent even before the pandemic, affecting 10-30% of the population. If the vaccines had been available then, many might have been classified as suffering from long-Covid or PVS.

Research indicates that Covid-19 vaccines protect against long-Covid, with a 2023 meta-analysis showing a 36% reduction in long-Covid risk among vaccinated individuals.

Conclusion

In summary, while the LISTEN study presents compelling evidence regarding the association between Covid-19 vaccinations and PVS, it remains speculative. The median 3-day interval between vaccination and symptom onset raises questions, but the study's observational nature and lack of control groups mean its findings cannot be generalized to the wider population.

Considering potential confounding factors, the true prevalence of PVS among vaccinated individuals may be lower than the reported 241 cases. The principle of innocent until proven guilty should apply to Covid-19 vaccines until more comprehensive research provides clearer answers.

For further insights, I have written extensively about long-Covid on Medium, which remains relevant. Feel free to explore my work for additional context.

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