1. Office of Vaccines Research and Review, U.S. Food and Drug Administration/Center for Biologics Evaluation and Research, Silver Spring, MD, USA.
2. Division of Microbial and Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
3. Centers for Disease Control and Prevention, Atlanta, GA, USA.
4. Walter Reed Army Institute of Research, Silver Spring, MD, USA.