Figure 1. Flow chart of study design and volunteer recruitment.

20 participants were excluded following screening for the following reasons: significant psychiatric history (six individuals), consent withdrawn (four individuals), recruitment complete (2 individuals), lack of response from General Practitioner to medical screening letter (2 individuals), unexplained systolic murmur, elevated alanine transaminase, unexplained tachycardia and significant prior malaria exposure. In each group, the total dose of sporozoites was split between two injection sites and administered as two 50 µL injections, one in each deltoid.