Mild Cognitive Impairment 2.3 X more likely if 2 COVID vaccinations

A potential association between COVID-19 vaccination and development of Alzheimer’s disease

QJM: An International Journal of Medicine, Volume 117, Issue 10, October 2024, Pages 709–716, https://doi.org/10.1093/qjmed/hcae103

BackgroundThe challenges of the COVID-19 pandemic extend to concerns about vaccine side effects, particularly potential links to neurodegenerative diseases such as Alzheimer’s disease (AD).

AimThis study investigates the association between COVID-19 vaccination and the onset of AD and its prodromal state, mild cognitive impairment (MCI).

DesignA nationwide, retrospective cohort study leveraging data from the Korean National Health Insurance Service was conducted.

MethodsThe study, conducted in Seoul, South Korea, analyzed data from a random 50% sample of city residents aged 65 and above, totaling 558,017 individuals. Participants were divided into vaccinated and unvaccinated groups, with vaccinations including mRNA and cDNA vaccines. The study focused on AD and MCI incidences post-vaccination, identified via ICD-10 codes, using multivariable logistic and Cox regression analyses. Patients with vascular dementia or Parkinson’s disease served as controls.

ResultsFindings showed an increased incidence of MCI and AD in vaccinated individuals, particularly those receiving mRNA vaccines, within three months post-vaccination. The mRNA vaccine group exhibited a significantly higher incidence of AD (odds ratio [OR]: 1.225; 95% confidence interval [CI]: 1.025–1.464; P = 0.026) and MCI (OR: 2.377; CI: 1.845–3.064; P < 0.001) compared to the unvaccinated group. No significant relationship was found with vascular dementia or Parkinson’s disease.

ConclusionsPreliminary evidence suggests a potential link between COVID-19 vaccination, particularly mRNA vaccines, and increased incidences of AD and MCI. This warrants the need for further research to elucidate the relationship between vaccine-induced immune responses and neurodegenerative processes, advocating for continuous monitoring and investigation into the vaccines' long-term neurological impacts.

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Compare MCI with Dementia - Perplexity AI Nov 2025

Three of the 17 studies that cited the study as of Nov 2025

• Association between vaccinations and risk of dementia: a systematic review and meta-analysis Nov 2025
  other vaccines DECREASE the incidence of Alzheimer's https://doi.org/10.1093/ageing/afaf331

• Response to: Possible biases in Roh et al.’s article about the association between COVID-19 vaccination and Alzheimer’s disease
  Oct 2024 https://doi.org/10.1093/qjmed/hcae139 Author has some doubts

• Association between COVID-19 Vaccination and Neuropsychiatric Conditions
  April 2025 preprint. Many neurocognitive red flags in VAERS