Example of the analysis considering five MCI with intervals of 24

Evolution of the infection at each site is followed over time using a spreadsheet (all data can be found as Table S1). We consider the formula where No is the initial dose (100 CFUs), and t is the time in days. We highlight in bold italics the total bacillary load in the lung (sum) at the time when the immune response induced the stationary level in the model of single infection (1,195,374 and 135,952 CFUs for naïve and vaccinated mice, respectively). At this time the stationary level is reached at each infection site where there is a minimal bacillary concentration (135,952 CFUs, in bold). This is why, in contrast to what happens in a single infection model, the first infection stops before reaching 1,195,374 CFUs (i.e. on day 18 at 501,022 CFUs). The stationary level is therefore reached at all sites except site 5, which has not reached the minimal bacillary concentration.In the case of BCG-vaccinated mice, the stationary level at each site could be reached earlier as the sum on day 13 is 143,228. This exceeds the level of 135,952 bacilli, and thus the immune response is ready. However, there is insufficient bacillary load locally, which is why the stationary level is not immediately reached at each infection site. This illustrates how important it is for the local bacillary load to have the benefit of the immune response.