1. Center for Biostatistics in AIDS Research; Harvard TH Chan School of Public Health, Boston, Massachusetts, USA.
2. Department of Biostatistics, Harvard TH Chan School of Public Health, Boston, Massachusetts, USA.
3. Department of Biostatistics and Epidemiology, Rutgers School of Public Health, Piscataway, New Jersey, USA.
4. Division of Infectious Diseases, Children's Hospital of Los Angeles, Los Angeles, California, USA.