I make no apology for copying this from Jon Rappoport's blog... this needs putting out there...   The CDC document is titled, “CDC 2019-Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel.” It is dated July 13, 2020.  Link;  https://www.fda.gov/media/134922/download    Buried deep in the document, on page 39, in a section titled, “Performance Characteristics,” we have this: “Since no quantified virus isolates of the 2019-nCoV are currently available, assays [dia