Determination of daily reproduction numbers of SARS-CoV2 based on death cases suggests more rapid initial spread in Italy and the United States

Armin Ensser; Klaus Ueberla

A superior integration standard would contain multiple unique integration sites (thousands or more), all integrated randomly at a range of distances from the nearest Alu repeat sequence. Recently, the first fully quantitative one-step kinetic Alu PCR assay for HIV-1 integration was described (5) . It was shown to be capable of detecting as few as one provirus in 100 target cells. The importance of appropriate standardization was emphasized, in particular the need for a standard that accurately reflected the random nature of integration. An integration standard was generated by infection of 293T cells with a high titer of virus, followed by a culture period of at least 30 days, to allow unintegrated forms of HIV-1 DNA to be eliminated (1, 16, 30) . Only then was genomic DNA prepared.