MAPT and Alzheimer disease: Prion-like domains are known to self-associate, aggregate with other prion-like and HBP domains and amyloids, α-synuclein, tau and other prion proteins and contribute to protein-misfolding diseases that include AD and PrD infection (Holmes et al., 2010; Geschwind, 2015; Ayers et al., 2020); and (ii) there are several recent case studies of patients developing PrD and or exacerbating the neuropathology of PrDs such as CJD in conjunction with SARS-CoV-2 infection.