Figure 1.

IFN-γ response to M.tb PPD at baseline, and at 3 and 12 months following BCG vaccination, among teenage unvaccinated controls and vaccinees. Control subjects n = 62, vaccinated subjects n = 86. Each box shows the median and 25^th and 75^th centiles. The "whiskers" show the minimum and maximum values other than outliers which are represented as dots above the "whiskers". Grey line represents threshold of positive IFN-γ response (> 62 pg/ml; twice the limit of detection of the assay (31 pg/ml) [13]).