Nir Eyal1,2,3, Marc Lipsitch4,5, Peter G Smith6. 1. Center for Population-Level Bioethics, Rutgers University, New Brunswick, New Jersey, USA. 2. Department of Philosophy, Rutgers University, New Brunswick, New Jersey, USA. 3. Department of Health Behavior, Society and Policy, Rutgers School of Public Health, Piscataway, New Jersey, USA. 4. Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA. 5. Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA. 6. MRC Tropical Epidemiology Group, London School of Hygiene & Tropical Medicine, London, UK.