Fig. 2

Scale-up of RNTCP services. Blue points show data for the proportion of geographical coverage of RNTCP [33], while red points show data for the proportion of geographical coverage of PMDT for MDR-TB [33]. As described in the text, these data were used to determine logistic functions capturing the timing and pace (‘steepness’) of scale-up. Resulting functions are superimposed as blue and red curves, with the following parametric forms: F(t) = 1/[1 + Exp(4 · 2 - 0 · 76* t)] (RNTCP scale-up), G(t) = 1/[1 + Exp(20 - 1 · 37* t)] (PMDT scale-up). Note that a value of 1 on the y-axis does not imply that the proportion of TB patients treated by RNTCP is 100%; rather, this proportion is given by p _max F(t), where p _max is a parameter to be estimated (see Methods). That is, F(t) (and similarly G(t)) simply represent the proportion of ultimate coverage reached, at a given time during scale-up