1. From the Biomedical Advanced Research and Development Authority, Administration for Strategic Preparedness and Response, Department of Health and Human Services, Washington, DC (H.C.M., B.G.K., D.N.W.); Tunnell Government Services, Berwyn, PA (H.C.M.); and the Dartmouth International Vaccine Initiative at the Geisel School of Medicine at Dartmouth, Hanover, NH (H.C.M.).