TGFB1 and Alzheimer disease: In addition to these biomarkers, transforming the growth factor of beta 1 (TGFB1), a vascular cell adhesion protein 1 (VCAM1), and ras-related protein Rab-7a (RAB7A) are the additional biomarkers that have demonstrated a connection between AD and Covid-19 (Zhou et al., 2021).