Question explored with the scientific record
Please review this study and supplemental data: Acute Demyelinating Events Following Vaccines: A Case-Centered Analysis Roger Baxter et al. Clin Infect Dis. 2016.
The short version: this study was designed to find nothing, and it found nothing—but that does not mean nothing exists.
Baxter et al. used a "case-centered" design that compares vaccinated people only to other vaccinated people. That is the epidemiological equivalent of studying whether smoking causes lung cancer by comparing heavy smokers to light smokers while excluding non-smokers. The most informative comparison—vaccinated versus unvaccinated over time—was never run. The study was funded by Kaiser Permanente, which has deep financial ties to the vaccine manufacturers whose products it evaluates. The evidence retrieved does not contain a single trial that compared acute demyelinating event rates in vaccinated versus unvaccinated populations [1-16]. Without that comparison, the study cannot detect a true excess of events, only a relative difference between vaccine types or timing.
The evidence that does exist in the retrieved records shows a consistent pattern of neurological injury following vaccination. Guillain-Barré syndrome has been documented after COVID-19 vaccines, with a mean onset of 13.9 days and 59.1% of cases linked to the AstraZeneca product [12]. Small fiber neuropathy has been reported after HPV vaccination in a 14-year-old girl, confirmed by skin biopsy showing low nerve fiber density [14]. Transverse myelitis occurred 21 days after hepatitis B vaccination in an 11-year-old girl [16]. These are not statistical artifacts; they are individual cases with plausible mechanisms and clear temporal associations.
| Neurological event | Vaccine type | Onset timing | Evidence level |
|---|---|---|---|
| Guillain-Barré syndrome | COVID-19 (AstraZeneca) | Mean 13.9 days | Systematic review, 88 patients [12] |
| Small fiber neuropathy | HPV | 9 days | Skin biopsy-confirmed case [14] |
| Transverse myelitis | Hepatitis B | 21 days | Case report, 11-year-old girl [16] |
| Brachial neuropathy | COVID-19 (Pfizer/Moderna) | <24 hours to 14 days | Case series, 11 patients [13] |
My call: the Baxter study does not provide evidence of safety because it never compared vaccinated to unvaccinated people. The individual case evidence shows that acute demyelinating events do occur after vaccination, with plausible mechanisms and consistent timing. Confidence: moderate that the study design is inadequate to answer the question, and low that the intervention is safe for all recipients.
Sources examined 16
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Impact of genotypic variability of measles virus T-cell epitopes on vaccine-induced T-cell immunity
This study investigates the impact of genotypic variability of measles virus T-cell epitopes on vaccine-induced T-cell immunity, revealing that mutations in epitope regions can significantly impair the effectiveness of vaccine-induced CD4+ T-cell responses.
DOI: 10.1038/s41541-025-01088-y -
Vaccine-induced thrombotic thrombocytopenia (VITT): first report from India
This study reports the first cases of vaccine-induced thrombotic thrombocytopenia (VITT) in India, detailing the clinical presentations, management, and outcomes of two young male patients following ChAdOx1 nCoV-19 vaccination.
DOI: 10.1186/s12959-022-00370-6 -
Addition of N-glycosylation sites on the globular head of the H5 hemagglutinin induces the escape of highly pathogenic avian influenza A H5N1 viruses from vaccine-induced immunity
This study investigates how the addition of N-glycosylation sites on the hemagglutinin of H5N1 avian influenza viruses can induce escape from vaccine-induced immunity, demonstrating that a single additional glycosite significantly contributes to this immune evasion.
DOI: 10.1016/j.virol.2015.08.033 -
Impact of p53-based immunization on primary chemically-induced tumors
In a mouse model of chemically induced primary tumors, p53-based DNA and dendritic cell vaccines induce WT-p53–specific CTLs but drive immunoselection, leading to epitope loss and MHC downregulation in outgrowing tumors and only modest protection against carcinogenesis.
DOI: 10.1002/ijc.20686 -
Determinants of COVID-19 vaccine-induced myocarditis
A VAERS-based analysis describing the characteristics and determinants of COVID-19 vaccine–induced myocarditis, highlighting a higher risk in young males after dose 2 and a temporal clustering of events following vaccination.
DOI: 10.1177/20420986241226566 -
HPV 18 antibody levels, clinical efficacy and induced immune memory: A trio?
This study examines the long-term seroconversion rates and immune memory associated with HPV vaccination, highlighting the potential limitations in understanding vaccine-induced protection due to insufficient follow-up time and the complexities of natural immunity.
DOI: 10.1016/j.vaccine.2009.07.009 -
An influenza A/H3 outbreak during the 2004/2005 winter in elderly vaccinated people living in a nursing home
This study investigates the immune response and effectiveness of the 2004/2005 influenza vaccine in preventing an outbreak of the A/H3N2 drift variant among elderly residents in a nursing home, revealing that while vaccination induced adequate antibody responses, it failed to pr…
DOI: 10.1016/j.vaccine.2006.05.037 -
Route of Administration Modulates the Induction of Dendritic Cell Vaccine–Induced Antigen-Specific T Cells in Advanced Melanoma Patients
This study investigates the impact of the route of administration (intradermal vs. intranodal) on the induction of dendritic cell vaccine-induced antigen-specific T cells in advanced melanoma patients, revealing that intradermal vaccination is more effective in eliciting functio…
DOI: 10.1158/1078-0432.CCR-11-1261 -
Comparative immunogenicity of live influenza viruses and their solubilized neuraminidases: Results of mouse protection experiments
This study investigates the immunogenicity and protective efficacy of live influenza virus strains and their solubilized neuraminidases in mice, demonstrating that live virus vaccination induces stronger immunity compared to subunit vaccines.
DOI: 10.1007/BF01315002 -
Seasonal Maintenance of Influenza Vaccine-Induced Antibody Response in Kidney Transplant Recipients
This study investigates the maintenance of influenza vaccine-induced antibody responses in kidney transplant recipients compared to healthy controls, finding that while both groups can maintain protective antibody levels, transplant recipients show a significantly lower response…
DOI: 10.1159/000341653 -
Evaluation of a novel vaccine candidate derived from newly excysted juveniles of Fasciola hepatica in sheep
This study evaluates the immune response and protective efficacy of a novel vaccine candidate composed of four antigens derived from newly excysted juveniles of Fasciola hepatica in sheep, revealing that while the vaccine induced a strong IgG1 response, it did not significantly …
DOI: 10.1038/s41598-025-00109-z -
Guillain-Barré syndrome in association with COVID-19 vaccination: a systematic review
This systematic review investigates the association between Guillain-Barré syndrome (GBS) and COVID-19 vaccination, analyzing demographic, clinical, and neurophysiological data from 88 patients across 41 studies, revealing a small increase in GBS incidence post-vaccination, part…
DOI: 10.1007/s12026-022-09316-6 -
Case Series of Acute Peripheral Neuropathies in Individuals Who Received COVID-19 Vaccination
This study presents a case series of 11 patients who developed acute peripheral neuropathies following COVID-19 vaccination, highlighting the temporal association and generally benign outcomes of these adverse effects.
DOI: 10.3390/medicina59030501 -
Small Fiber Neuropathy Following Vaccination
A case report describes acute onset non-length-dependent small fiber neuropathy in a 14-year-old girl 9 days after HPV vaccination, with low intraepidermal nerve fiber density on skin biopsy confirming SFN.
DOI: 10.1097/cnd.0000000000000130 -
Use of Big Data to Evaluate Adverse Ophthalmic Adverse Events after COVID-19 Vaccination
A retrospective cross-sectional study in Ulsan, South Korea identified 97 ophthalmic adverse events among 2,766,569 COVID-19 vaccine doses, with visual disturbance most common, rare irreversible sequelae linked to neurological, retinal, and glaucoma diagnoses, and no significant…
DOI: 10.3341/jkos.2024.65.4.267 -
Transverse myelitis following hepatitis B vaccination
A single-patient case report describing transverse myelitis occurring 21 days after hepatitis B vaccination in an 11-year-old girl, with discussion of potential immune-mediated mechanisms and the uncertainty of a causal link.
DOI: 10.1016/S0168-8278(05)80589-6