1. Center for Research in Infectious Diseases, National Institute of Respiratory Diseases, Mexico City, Mexico
2. Coordinating Commission of the National Institutes of Health and High Specialty Hospitals, Ministry of Health, Mexico City, Mexico
3. Clínica Especializada Condesa, Mexico City, Mexico
4. Division of Infectious Diseases and Global Public Health, University of California, San Diego, San Diego, California, USA
5. Veterans Affairs Health System, San Diego, California, USA