Collaborations with Sanaria Inc and the Malaria Research and Training Center at the University of Bamako, Mali to conduct these PfSPZ related studies was initiated in 2012. PfSPZ CVac in Mali In 2012, we initially developed a clinical trials protocol for a PfSPZ CVac study to be conducted in Mali. All required approvals had been obtained and study site preparation completed by December 2012. Due to the civil unrest in Mali the trial could not be start in April 2013 as planned. Later in 2013, recruitment for this research study was never initiated as the start of this study in Mali was linked to the study team receiving and reviewing the safety and efficacy results from a similar study at Radboud University in Nijmegen, The Netherlands. The study in Nijmegen showed that three and four immunizing intradermal doses of 75,000 PfSPZ were safe and well tolerated. However, the regimen of three and four doses of 75,000 PfSPZ, administered by multiple intradermal injections under chloroquine prophylaxis, did not confer sufficient protection against the bites of mosquitoes infected with the homologous Pf strain and thus does not warrant at this time the regimen proceeding to Mali for further evaluation. Given these results, the study was closed with the IRBs in July 2014. PfSPZ Vaccine in Mali Since January 2013, we have been preparing for a study to test the safety, immunogenicity and efficacy against naturally occurring malaria infection of PfSPZ Vaccine in Malian adults. The phase 1 double-blind, randomized, controlled trial to assess the safety, immunogenicity, and protective efficacy of repeated IV immunization with PfSPZ Vaccine in Mali started in January 2014 in Doneguebougou, Mali at the Malaria Research and Training Center with complete enrollment into the study by February 2014. One hundred and nine healthy adults were enrolled into the study in a protocol specified staggered, dose escalating manner. The study subjects have just completed, as of July 2014, the series of vaccination as outlined in the protocol. Follow-up during the malaria transmission season will continue until January 2015 to assess the protective efficacy of repeated IV immunization with PfSPZ Vaccine against naturally occurring infection. Subjects will complete their final study visit in January 2015 and the study will be unblinded at that final study visit to both the investigators and the subjects.