A Response to Defenses Against our Critique on Cohort Composition in the Kim et al. COVID-19 Vaccine Study (Biomark Res, 13:114, 2025)

Introduction and Disclaimer The details of our quantitative critique on the methodology of the Kim et al. study 1 can be found in our preprints 2-6. Our analysis is not focused on whether COVID-19 vaccines are biologically associated with Serious Adverse Events (SAE) or cancer risk. Instead, our core finding is that the cohort used in the scrutinized study is fundamentally flawed and unreliable due to a severe methodological error in participant selection. I will now explain, using quantitative metrics, why the study's reported association is a statistical artifact and not a genuine biological signal.