Before revision:  Our system has just become achievable with present technology : for each positive case, do not only notify their direct contacts , but inform thousands of people of how far away they are from the positive case, as measured in network-theoretic distance in their physical relationship network. This fundamentally different approach has already been deployed in a publicly downloadable app . It brings a new tool to bear on the pandemic , powered by network theory.
After revision:  Our system has just become achievable with present technology : for each positive case, do not only ask direct contacts to quarantine; instead, tell everyone how many relationships away the disease just struck (so, "2" is a close physical contact of a close physical contact). This new approach, which has already been deployed in a publicly downloadable app . It brings a new tool to bear on the pandemic , powered by network theory.