Complex chronic adverse events following immunization: a systemic critique and reform proposal for vaccine pharmacovigilance

Abstract:

The COVID-19 pandemic has renewed attention to complex chronic health conditions that challenge conventional biomedical paradigms. Syndromes such as postural orthostatic tachycardia syndrome and myalgic encephalomyelitis/chronic fatigue syndrome have gained broader visibility through the lens of Long COVID. As global vaccination campaigns expanded, a subset of individuals began reporting similarly persistent, multisystem symptoms following COVID-19 immunization-informally referred to as post-COVID-19 vaccination syndrome.

These presentations, which include dysautonomia, neuropathic pain, post-exertional malaise, and cognitive dysfunction, resemble post-infectious syndromes and may involve shared immune-related mechanisms. Although no causal relationship to vaccination has been established, these cases-together with comparable reports following other vaccines-highlight limitations in current vaccine safety systems for detecting and evaluating complex chronic outcomes.

This article introduces the concept of complex chronic adverse events following immunization (CC-AEFIs) as a pragmatic, surveillance-oriented framework to support the systematic identification and investigation of such cases. CC-AEFIs are not syndromic diagnoses but a higher-order category encompassing persistent, multifactorial conditions that may follow immunization yet challenge existing pharmacovigilance definitions and tools.

These conditions often involve multiple organ systems, delayed onset, fluctuating trajectories, diagnostic ambiguity, and symptom heterogeneity. Drawing on the author’s lived experience as an affected patient and integrating clinical, regulatory, and experiential evidence, the analysis examines structural and epistemic limitations across the pharmacovigilance continuum-from underrecognition in clinical settings to analytic exclusion and constrained governance.

It concludes by proposing reforms to strengthen safety-system responsiveness, including enhanced diagnostic training, longitudinal surveillance, patient-reported outcome integration, and analytic transparency. Addressing these limitations is essential to sustain public trust, ensure equitable care, and uphold the scientific integrity of immunization programs.

Source: Kenny TA. Complex chronic adverse events following immunization: a systemic critique and reform proposal for vaccine pharmacovigilance. Ther Adv Drug Saf. 2025 Dec 24;16:20420986251395925. doi: 10.1177/20420986251395925. PMID: 41466718; PMCID: PMC12743803. https://pmc.ncbi.nlm.nih.gov/articles/PMC12743803/ (Full text)

Myalgia and chronic fatigue syndrome following immunization: macrophagic myofasciitis and animal studies support linkage to aluminum adjuvant persistency and diffusion in the immune system

Abstract:

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a multifactorial and poorly undersood disabling disease. We present epidemiological, clinical and experimental evidence that ME/CFS constitutes a major type of adverse effect of vaccines, especially those containing poorly degradable particulate aluminum adjuvants.

Evidence has emerged very slowly due to the multiplicity, lack of specificity, delayed onset, and frequent medical underestimation of ME/CFS symptoms. It was supported by an epidemiological study comparing vaccinated vs unvaccinated militaries that remained undeployed during Gulf War II.

Affected patients suffer from cognitive dysfunction affecting attention, memory and inter-hemispheric connexions, well correlated to brain perfusion defects and associated with a stereotyped and distinctive pattern of cerebral glucose hypometabolism. Deltoid muscle biopsy performed to investigate myalgia typically yields macrophagic myofasciitis (MMF), a histological biomarker assessing longstanding persistency of aluminum agglomerates within innate immune cells at site of previous immunization. MMF is seemingly linked to altered mineral particle detoxification by the xeno/autophagy machinery.

Comparing toxicology of different forms of aluminum and different types of exposure is misleading and inadequate and small animal experiments have turned old dogma upside down. Instead of being rapidly solubilized in the extracellular space, injected aluminum particles are quickly captured by immune cells and transported to distant organs and the brain where they elicit an inflammatory response and exert selective low dose long-term neurotoxicity. Clinical observations and experiments in sheep, a large animal like humans, confirmed both systemic diffusion and neurotoxic effects of aluminum adjuvants. Post-immunization ME/CFS represents the core manifestation of “autoimmune/inflammatory syndrome induced by adjuvants” (ASIA).

Copyright © 2019. Published by Elsevier B.V.

Source: Gherardi RK, Crépeaux G, Authier FJ. Myalgia and chronic fatigue syndrome following immunization: macrophagic myofasciitis and animal studies support linkage to aluminum adjuvant persistency and diffusion in the immune system. Autoimmun Rev. 2019 May 3. pii: S1568-9972(19)30109-0. doi: 10.1016/j.autrev.2019.05.006. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/31059838

Precipitating factors for the chronic fatigue syndrome

Abstract:

The etiology of the Chronic Fatigue Syndrome (CFS) is unknown but it is usually considered to be postinfectious or postviral. Many infecting agents have been suspected as causative but none has been proven.

We investigated precipitating factors in 134 CFS patients through the use of a questionnaire, interview, clinical examination and serology for infecting agents; 35 healthy controls completed a similar questionnaire. CFS started with an apparently infectious illness in 96 (72%) but a definite infection was only found in seven of these 96 (7%). Thirty-eight (28%) had no apparent infectious onset: 15/38 (40%) had noninfectious precipitants (trauma, allergy, surgery).

There was no apparent precipitating event in 23/38 (61%). Immunization was not a significant precipitant. Stressful events were very common in the year preceding the onset of CFS (114/134, 85%) but these occurred in only 2/35 (6%) of the controls (p < .0001). The onset of CFS may be associated with preceding stressful events and multiple other precipitants. An infectious illness is not uniformly present at the onset and no single infectious agent has been found; CFS is most likely multifactorial in origin.

 

Source: Salit IE. Precipitating factors for the chronic fatigue syndrome. J Psychiatr Res. 1997 Jan-Feb;31(1):59-65. http://www.ncbi.nlm.nih.gov/pubmed/9201648