Abstract: Transmission of misfolded amyloid-β (Aβ) aggregates between human subjects: Protein misfolding disorders are a family of diseases characterized by the accumulation of misfolded protein aggregates. These proteinaceous structures, also known as amyloids, are key drivers of fatal neurodegenerative disorders such as prion diseases, Alzheimer’s disease (AD), Parkinson’s disease, and others. The amyloidogenic proteins underlying these neuropathologies vary and include infectious prion protein (PrPSc, prion diseases), Aβ (AD), and α-synuclein protein (Parkinson’s disease). Clinical and experimental studies have established a causal relationship between the physicochemical properties of PrPSc and disease in humans (e.g., Creutzfeldt-Jakob disease [CJD]) as well as various other species (e.g., bovine spongiform encephalopathy in cattle, chronic wasting disease in cervids, and scrapie in sheep and goats). Hence, PrPSc is distinguished as a proteinaceous agent able to satisfy Koch’s postulates and remains the sole hallmark of inter-individual transmissible proteinopathies (e.g., iatrogenic CJD [iCJD]) (Brown et al., 2012). Interestingly, studies have convincingly demonstrated that under experimental settings the aberrant conformation of Aβ exhibits numerous features akin to those of PrPSc: highly-ordered and β-sheet-rich protein aggregates, self-propagating properties, and propensity to accumulate in distinct areas of the brain associated with progressive neurodegeneration and cognitive decline, among others (Walker et al., 2016). In turn, reinvigorating efforts have been made to determine whether human-to-human transmission of Aβ aggregates is feasible. Comprehensive reviews by us and others have detailed the results of these studies; wherein reports indicate that inter-human transmission of Aβ-amyloids can occur through medical procedures such as growth hormone treatment and dura mater transplant, albeit rarely, and results in a notably different neuropathology compared to that of AD (Gomez-Gutierrez and Morales, 2020; Lauwers et al., 2020). Following, we address these observations.