1. From Novavax, Gaithersburg, MD (V.S., L. Fries, S.C.-C., M.Z., C.B., G.A., E.F., J.S.P., A.R., S.N., I.C., G.M.G., F.D.); and the South African Medical Research Council, Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences (S.B., V.B., A.L.K., A.O.-J., A.T., S.A.M.), Wits Reproductive Health and HIV Institute (L. Fairlie, G.B.), University of the Witwatersrand, and Soweto Clinical Trials Centre (Q.B., A.E.B.), Johannesburg, Josha Research Centre, Bloemfontein (Z.H., J.J.L....