1. Infectious Disease Clinical Research Program, Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
2. Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc, Bethesda, Maryland, USA
3. Emory Vaccine Center, Rollins School of Public Health, Emory University School of Medicine, Atlanta, Georgia, USA
4. Atlanta Veterans Affairs Medical Center, Atlanta, Georgia, USA