1. Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, USA
2. Department of Biostatistics and Epidemiology, Rutgers School of Public Health, Piscataway, NJ, USA
3. Empilweni Services and Research Unit, Rahima Moosa Mother and Child Hospital, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
4. Perinatal HIV Research Unit, Chris Hani Baragwanath Hospital, University of the Witwatersrand, Johannesburg, South Africa
5. Department of Epidemiology & Biostatistics, University of California, San Francisco, CA, USA
6. HIV Center for Clinical and Behavioral Studies, New York Psychiatric Institute and Columbia University, New York, NY, USA
7. Department of Medicine, Columbia University Medical Center, New York, NY, USA
8. Department of Pediatrics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
9. ICAP, Mailman School of Public Health, Columbia University, New York, NY, USA
10. Gertrude H. Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, NY, USA