Vaccine and Infectious Disease Division and Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.|Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, Georgia, United States of America.|Department of Biostatistics, University of Washington, Seattle, Washington, United States of America.|Vaccine and Infectious Disease Division and Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.|Vaccine and Infectious Disease Division and Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.|Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America.|Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America.|Division of Basic Sciences and Computational Biology Program, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.|Department of Biostatistics, University of Washington, Seattle, Washington, United States of America.|Department of Biostatistics, University of Washington, Seattle, Washington, United States of America.|Vaccine and Infectious Disease Division and Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.|Duke University School of Medicine, Duke University, Durham, North Carolina, United States of America.|Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts, United States of America.|Ragon Institute of MGH, MIT and Harvard, Cambridge, Massachusetts, United States of America.|Vaccine and Infectious Disease Division and Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.|Vaccine and Infectious Disease Division and Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.|Vaccine and Infectious Disease Division and Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.|University of Zimbabwe College of Health Sciences Clinical Trials Research Centre, Harare, Zimbabwe.|Department of Medicine, Division of Infectious Diseases, Emory University, Atlanta, Georgia, United States of America.|Vaccine and Infectious Disease Division and Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.