Author: John Murphy, The COVID-19 Long-haul Foundation

Abstract From December 2020 through mid-2025, the Vaccine Adverse Event Reporting System (VAERS) received over 1.3 million reports related to COVID-19 vaccines, including thousands of entries describing neurological symptoms. This article presents a structured analysis of neurological signal clusters, including Guillain–Barré syndrome, small fiber neuropathy, dysautonomia, seizures, and tinnitus, among others. Drawing on VAERS data and supported by peer-reviewed literature, we examine patterns of onset, severity, and persistence. The findings raise critical questions about long-term neuroimmune consequences and underscore the need for rigorous longitudinal studies and transparent safety governance.

Introduction The COVID-19 vaccine rollout, initiated under Emergency Use Authorization in late 2020, marked a turning point in global public health. While the vaccines were deployed rapidly to mitigate viral spread, long-term safety data were necessarily incomplete at launch. In the United States, VAERS became the primary repository for adverse event reporting, capturing both mild and serious reactions across millions of doses.

VAERS is a passive surveillance system, not designed to establish causality. However, it remains a vital tool for signal detection, especially when patterns emerge across time, dose, and demographic strata. Among the most concerning signals are those involving neurological sequelae—conditions that may persist, evolve, or impair quality of life long after vaccination. This article synthesizes five years of VAERS data and peer-reviewed findings to characterize these neurological clusters and explore their implications for long-haul syndromes.

Methods VAERS data from December 2020 through July 2025 were accessed via the CDC’s public interface. Reports were filtered for COVID-19 vaccine entries and stratified by age, sex, manufacturer, dose number, and reported outcome. Neurological adverse events were identified using MedDRA Preferred Terms (PTs) and grouped into clinically coherent clusters. Severity proxies included hospitalization, life-threatening designation, disability, and death. Time-to-onset distributions were analyzed to distinguish acute from delayed presentations.

To contextualize VAERS findings, we reviewed ten peer-reviewed studies that examined neurological outcomes following COVID-19 vaccination using VAERS, EudraVigilance, and other pharmacovigilance systems. These studies employed disproportionality analysis, cohort comparisons, and mechanistic exploration.

Results

Volume and Distribution

VAERS received over 1.3 million COVID-19 vaccine-related reports during the study period. Of these, approximately 20,000 involved death, and over 100,000 described neurological symptoms. The majority of neurological reports occurred within 14 days of vaccination, with clustering around days 1–3 and 7–10.

Signal Clusters

Guillain–Barré Syndrome (GBS) and Variants

GBS was disproportionately reported following adenoviral vector vaccines, particularly Johnson & Johnson’s Jcovden. A 2025 study using EudraVigilance found a PRR of 5.4 for polyradiculoneuropathy following Jcovden, with a 95% confidence interval of 3.98–7.32. VAERS narratives frequently described ascending weakness, areflexia, and hospitalization. A subset evolved into chronic inflammatory demyelinating polyneuropathy (CIDP), suggesting possible long-haul trajectories.

Small Fiber Neuropathy (SFN) and Paresthesia

Reports of burning pain, tingling, and dysesthesia were common, often co-occurring with autonomic symptoms. These presentations were more frequent in younger adults and women. Persistence was flagged in over 40% of cases, with many marked “not recovered” at the time of reporting. Peer-reviewed analysis confirmed SFN-like symptoms as statistically enriched adverse events.

Dysautonomia and POTS-like Syndromes

Postural orthostatic tachycardia syndrome (POTS), palpitations, and orthostatic intolerance were reported across all vaccine platforms. These symptoms often emerged within 7 days and persisted for months. A 2023 review in JAMA Neurology highlighted dysautonomia as a plausible post-vaccinal neuroimmune phenomenon, especially in younger cohorts.

Seizures and Convulsive Events

Seizure reports peaked within 72 hours post-vaccination. While many involved individuals with prior seizure history, a significant fraction occurred in previously healthy individuals. Status epilepticus and hospitalization were documented in severe cases. Statistical enrichment was noted for seizure-related PTs in VAERS and EudraVigilance.

Tinnitus and Vestibular Disorders

Tinnitus was among the most frequently reported neurological symptoms, often described as sudden-onset and persistent. Co-reporting with dizziness, headache, and insomnia was common. A 2022 study found tinnitus to be significantly associated with mRNA vaccines, with a higher prevalence in females.

Demyelinating CNS Events

Optic neuritis, transverse myelitis, and multiple sclerosis relapses were reported, particularly after booster doses. A 2024 meta-analysis identified excess cases of transverse myelitis and neuromyelitis optica following vaccination, with PRRs exceeding 4.0. While causality remains unproven, the temporal clustering and recurrence upon re-exposure warrant further investigation.

Encephalitis and Encephalopathy

Reports of altered mental status, confusion, and autoimmune encephalitis were rare but severe. Hospitalization and ICU admission were common. A 2023 case series documented anti-NMDA receptor encephalitis following mRNA vaccination, suggesting a possible autoimmune trigger.

Movement Disorders and Tremor

Tremor, internal vibrations, and dystonia were reported across age groups. While many cases were transient, a subset described persistent symptoms interfering with daily function. Functional neurological disorder (FND) was suspected in some cases, but organic movement disorders were also documented.

Discussion The VAERS dataset reveals consistent patterns of neurological adverse events following COVID-19 vaccination. While causality cannot be established from passive surveillance, the volume, severity, and persistence of certain clusters—especially GBS, SFN, dysautonomia, and demyelinating events—suggest biologically plausible mechanisms and warrant targeted follow-up.

Several studies have employed disproportionality analysis to quantify these signals. For example, López de las Huertas et al. found elevated PRRs for multiple sclerosis and transverse myelitis following Jcovden. Guo et al. identified 96 statistically enriched neurological adverse events across three vaccine platforms using VAERS data2. These findings align with clinical observations and patient-reported outcomes from long-haul cohorts.

Mechanistically, post-vaccinal neuroimmune activation may involve molecular mimicry, bystander activation, or dysregulated cytokine responses. While these hypotheses remain under investigation, the clustering of symptoms and recurrence upon re-exposure support the need for mechanistic studies.

Importantly, many of these conditions—especially SFN, dysautonomia, and tinnitus—are under-recognized and under-reported. Their impact on quality of life can be profound, yet they often lack clear diagnostic pathways or treatment protocols. The COVID-19 Long-haul Foundation has documented dozens of such cases, many of which remain unresolved years after vaccination.

Conclusion Five years of VAERS data and peer-reviewed literature reveal significant neurological signal clusters following COVID-19 vaccination. While most adverse events are mild and transient, a subset involves serious, persistent, and disabling conditions. These findings challenge assumptions of universal safety and highlight the need for transparent, longitudinal research.

Public health policy must evolve to incorporate real-world safety signals, especially when they affect younger populations with low baseline risk. The precautionary principle demands that we investigate, not dismiss, these patterns. Only through rigorous science and open dialogue can we ensure that vaccine safety is not presumed—but proven.

References

1. López de las Huertas A, et al. Disproportionality Analysis of Neurological Effects of COVID-19 Vaccines. Pharmaceuticals. 2025;18(5):636. Link
2. Guo W, et al. Profiling COVID-19 Vaccine Adverse Events via VAERS Statistical Analysis. Front Pharmacol. 2022;13:870599. Link
3. Willison AJ, et al. SARS-CoV-2 Vaccination and Neuroimmunological Disease: A Review. JAMA Neurol. 2024;81(2):123–134. Link
4. Noseda R, et al. Seizure Reports Following COVID-19 Vaccination: A Pharmacovigilance Study. Drug Saf. 2023;46(3):245–256.
5. Formeister EJ, et al. Tinnitus and Hearing Loss After COVID-19 Vaccination: A Case Series.