Based on these and other very recent findings this “Opinion” paper will: (i) address our current understanding of the emerging role of SARS-CoV-2 infection with “long COVID” with special reference to AD and PrD; (ii) will review the latest findings of the SARS-CoV-2 “S1” spike protein and its preferred interaction with the ubiquitous angiotensin converting enzyme-2 (ACE2) receptor (ACE2R); and (iii) will highlight the interplay of the molecular biology and neuropathology of SARS-CoV-2 with the unusual and immune-evasive character of prion neurobiology, AD and PrD. Here, PROS1 is linked to Alzheimer disease.