Fig. 6: Effects of hybrid contact tracing protocol.
From: Stochastic sampling effects favor manual over digital contact tracing
a Plot, as a function of f2, of the ratio between the epidemic threshold in the presence of a hybrid CT protocol, \({r}_{{\mathrm{C}}}^{{\mathrm{MANUAL}}+{\mathrm{APP}}}\), and the epidemic threshold of the non-adaptive case, \({r}_{{\mathrm{C}}}^{{\mathrm{NA}}}\), for realistic values of \(\overline{\epsilon }\) (see legend). In the inset we plot, as a function of f2, the ratio between \({r}_{{\mathrm{C}}}^{{\mathrm{MANUAL}}+{\mathrm{APP}}}\) and the epidemic threshold when only manual CT is implemented, \({r}_{{\mathrm{C}}}^{{\mathrm{MANUAL}}}\). b Plot of the ratio \({r}_{{\mathrm{C}}}^{{\mathrm{MANUAL}}+{\mathrm{APP}}}/{r}_{{\mathrm{C}}}^{{\mathrm{NA}}}\) as a function of \(\overline{\epsilon }\), for realistic app adoption levels f (see legend). In the inset we plot, as a function of \(\overline{\epsilon }\), the ratio between \({r}_{{\mathrm{C}}}^{{\mathrm{MANUAL}}+{\mathrm{APP}}}\) and the epidemic threshold when only app-based CT is implemented, \({r}_{{\mathrm{C}}}^{{\mathrm{APP}}}\). c The ratio \({r}_{{\mathrm{C}}}^{{\mathrm{MANUAL}}+{\mathrm{APP}}}/{r}_{{\mathrm{C}}}^{{\mathrm{NA}}}\) is plotted as a function of f2 and \(\overline{\epsilon }\), through a heat map: the red dash-dotted lines are plotted for \(\overline{\epsilon }=0.3\) and f = 0.2, i.e., they correspond to the red dashed curves of panel a and b. In all panels the distribution ρ(aS, bS) is given by Eq. (1), the manual CT features a delay of τC = 3 days and limited scalability is considered.
