By contrast, for e~0:65, we see in Pane B that contact tracing drives infection to extinction, and from Pane D that this involves firstly higher levels of infection in the clustered system and then lower levels of infection for both the pairwise and stochastic models. We see a final reversal of the impact of clustering in Pane B, which is present in only the pairwise system: at longer times clustering again reduces the efficacy of contact tracing. At this point, stochastic variability in simulations has become highly significant and so we would not expect the two models to agree, since the pairwise equations should only hold in the limit where stochastic effects are negligible. To simulate in this regime would require extremely large population sizes, perhaps beyond what would ever be considered for realistic human scenarios.