Fig. 4

Distribution of change in IFN-gamma between visit 1 and visit 2 among HIV negative household contacts. a-d is shown for contacts (from both Zambia and South Africa) if they: a. had a valid QFT result available at visit 1 and visit 2; b. converted (< 0.2, ≥0.7); c. converted (< 0.2, ≥1.05); d. converted (< 0.2, ≥1.4). Baseline definition 2 (Table 1) was used to identify contacts with a valid (positive or negative) IFN-gamma value at visit 1 and 2