1 From the Department of Biostatistics, University of Florida, Gainesville (N.E.D., I.M.L.); the World Health Organization, Geneva (P.-S.G., A.M.H.-R.); the Department of Biostatistics, University of California, Los Angeles (R.B.); the Department of Biostatistics, Yale University, New Haven, CT (F.W.C.); the Department of Statistics (C.A.D.) and the Centre for Tropical Medicine and Global Health (P.H.), University of Oxford, Oxford, the Medical Research Council (MRC) Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London (C.A.D.), and the MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine (P.G.S.), London, and the Department of Mathematics and Statistics, Lancaster University, Lancaster (T.J.) - all in the United Kingdom; the Department of Biostatistics, Epidemiology, and Informatics, University of Pennsylvania, Philadelphia (S.S.E.); the Department of Biostatistics, University of Washington (T.R.F., M.E.H.), and the Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center (M.E.H.) - both in Seattle; the Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring (P.R.K.), and the Biostatistics Research Branch, National Institute of Allergy and Infectious Diseases, Bethesda (M.C.N.) - both in Maryland; Institut National de Recherche Biomédicale, Kinshasa, Democratic Republic of Congo (S.M., J.-J.M.-T.); and the Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute (R.W.), and the Department of Biostatistics, Harvard T.H. Chan School of Public Health (R.W., V.D.G.) - both in Boston.