Fig. 3

Distribution IFN-gamma results at visit 2 among HIV negative household contacts with a negative QFT result at visit 1. a. Zambia, all results (n = 172); b. South Africa, all results (n = 63). Baseline definition 2 (Table 1) was used to select contacts with a negative QFT result (< 0.35 IU/ml) at visit 1. No rules were applied to visit 2; all valid (positive and negative) IFN-g values were included