1. Division of AIDS, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland.
2. Department of Biostatistics, Harvard School of Public Health, Boston, Massachusetts.
3. University of California at San Francisco School of Medicine, San Francisco, California.
4. Center for Infectious Disease Control, RIVM, Bilthoven, The Netherlands; Julius Centre for Health Sciences and Primary Care, University Medical Centre Utrecht, Utrecht, The Netherlands.
5. National Institute of Mental Health, National Institutes of Health, Rockville, Maryland.
6. Bill and Melinda Gates Foundation, Seattle, Washington.
7. Department of Microbiology and Immunology, The University of North Carolina, Chapel Hill, North Carolina.