1. Division of HIV, Infectious Diseases, and Global Medicine, University of California , San Francisco, California , USA
2. Infectious Diseases Research Collaboration , Kampala , Uganda
3. Division of Research, Kaiser Permanente Northern California , Oakland, California , USA
4. Center for AIDS Prevention Studies (CAPS), University of California , San Francisco, California , USA
5. Department of Pediatrics, University of California , San Francisco, California , USA
6. School of Medicine, Makerere University , Kampala , Uganda
7. Division of Biostatistics, School of Public Health University of California , Berkeley, California , USA