Update on the Clinical Development of Candidate Malaria Vaccines W. Ripley Ballou, Myriam Arevalo-Herrera, Daniel Carucci, Thomas L. Richie, Giampietro Corradin, Carter Diggs, Pierre Druilhe, Birgitte K. Giersing, Allan Saul, D. Gray Heppner, Kent E. Kester, David E. Lanar, Jeff Lyon, Adrian V. S. Hill, Weiqing Pan, and Joe D Cohen