The HBO Vice special report on HIV "Countdown to Zero" visits laboratories where the DNA of HIV-positive patients is being edited to resist the virus. Penn Medicine's Clinical Cell and Vaccine Production Facility (CVPF) and Drs Carl June and Bruce Levine are featured starting at 35:22 as they explain the "zinc finger" gene editing technology that induces the CCR5 mutation in patients’ T cells in order to lock out the human immunodeficiency virus.