Our estimation of divergence times, with an evolutionary timescale spanning several decades, together with the extensive genetic distance between DRC60 and ZR59 indicate that these viruses evolved from a common ancestor circulating in the African population near the beginning of the twentieth century. To me he said: “This wasn’t a new virus in humans.” Worobey’s work directly refuted the OPV hypothesis. If HIV-1 existed in humans as early as 1908, then obviously it hadn’t been introduced via vaccine trials beginning in 1958.
