Part 2: Safety and Efficacy Part of this study will be conducted in the outpatient areas of Siaya County Referral Hospital, a large referral hospital in western Kenya and in Wagai dispensary. A maximum of 416 infants from 5 M to 12 M inclusive at vaccination will be enrolled into this safety and efficacy trial and randomized to receive PfSPZ Vaccine at a dose determined during Part 1 of the trial (dose escalation), but likely to be 4.5x10^5, 9.0 x10^5and 1.8 x 10^6 administered x 3 doses ; and NS placebo administered x 3 doses, all by DVI administered at 8 week intervals.