1. Division of Infectious Diseases and Global Public Health, Department of Medicine, University of California San Diego, La Jolla
2. Department of Computer Science, Barnard College, Columbia University, New York, New York
3. Department of Family Medicine and Public Health, Division of Health Policy, University of California San Diego, La Jolla
4. Department of Computer Science, Johns Hopkins University, Baltimore, Maryland
5. Department of Health Sciences, University of York, York, United Kingdom