• The claim appears to originate from a study that analyzed the U.S. Vaccine Adverse Event Reporting System (VAERS) and calculated proportional reporting ratios (PRRs) comparing COVID-19 vaccines to influenza vaccines¹².
• In that study, the PRR of 115 referred to general psychiatric illness adverse events, while cognitive impairment events had a PRR of 118—meaning these terms were reported more frequently in the VAERS database relative to flu vaccine reports, not that the actual clinical risk of cognitive decline is 115 times higher²¹.
• PRR measures disproportionate reporting frequency, not causal risk or incidence. VAERS is a passive, unverified system that accepts self-reported events without proof of causation, and fact-checkers have found similar PRR-based claims misleading because “unverified, self-reported data do not establish a causal link between vaccines and adverse events”³⁴.
• The Alzheimer’s Society explicitly states there is no evidence that COVID-19 vaccines worsen dementia or increase the likelihood of developing cognitive decline⁵.

Overall validity: 0%

1. Association between COVID-19 Vaccination and ...
2. Association Between COVID-19 Vaccination and Neuropsychiatric Conditions
3. Misleading to say brain clots '112000% more likely' after ... - AAP
4. Increase in COVID-19 VAERS Reports Due To Reporting Requirements, Intense Scrutiny of Widely Given Vaccines - FactCheck.org
5. Coronavirus (Covid) vaccines and dementia | Alzheimer's Society