Fig. 2

Distribution visit 1 IFN-gamma results among HIV negative household contacts with a valid IFN-gamma value. a. Zambia, all results (n = 797); b. Zambia, zoomed-in (0–1 IU/ml); c. South Africa, all results (n = 605); d. South Africa, zoomed-in (0–1 IU/ml). Baseline definition 2 (Table 1) was used to identify contacts with a valid (positive or negative) IFN-g value at visit 1