How to track COVID-19 without invading privacy

This article is part of our ongoing coverage of the fight against coronavirus. The past few months have taught us an important lesson: We're bad at handling highly contagious diseases. The Earth's growing population and the ease with which we can travel long distances have contributed to the fast spread of the novel coronavirus to more than 200 countries. For the moment, the main question is, how do we stop the spread of the virus? For states, the choice is between health and economy.