Table 6.

Regression coefficients for the effect of contact reductions and contact tracing parameters on growth rates across models with and without household structure and with individual- and household-level contact tracing. We performed 100 simulations for each model, with 5000 starting infections and estimated the growth rates using days 10–25 of the simulation. There is no interpretation of the intercept because we do not simulate scenarios where there is no contact tracing.

parameter	without household structure, test before trace	with household structure, test before trace, household-level tracing	with household structure, test before trace, individual-level tracing
intercept (instantaneous growth rate)	0.240 (0.220, 0.260)	0.240 (0.224, 0.256)	0.235 (0.220, 0.251)
reduction in global contacts (per 10% reduction in global contacts)	−0.0212 (−0.0310, −0.0114)	−0.0132 (−0.0211, −5.35 × 10−3)	−0.0151 (−0.0238, −0.0635)
(reduction in global contacts)2 (per 10% reduction in global contacts)	−4.02 × 10−3 (−8.47 × 10−4, 4.37 × 10−4)	−5.45 × 10−3 (−9.17 × 10−3, −1.72 × 10−3)	−3.56 × 10−3 (−7.32 × 10−5, 1.90 × 10−4)
(reduction in global contacts)3 (per 10% reduction in global contacts)	7.56 × 10−4 (1.15 × 10−5, 1.50 × 10−3)	8.36 × 10−4 (2.02 × 10−4, 1.47 × 10−3)	4.57 × 10−4 (−1.53 × 10−4, 1.06 × 10−3)
(reduction in global contacts)4 (per 10% reduction in global contacts)	−7.41 × 10−5 (−1.15 × 10−4, −3.32 × 10−5)	−5.98 × 10−5 (−9.50 × 10−5, −2.45 × 10−5)	−3.87 × 10−5 (−7.15 × 10−5, −5.78 × 10−6)
(probability of having the tracing app)2 (per 0.1 increase in probability)	−4.08 × 10−4 (−5.66 × 10−4, −2.49 × 10−4)	−1.23 × 10−4 (−2.70 × 10−4, 2.36 × 10−5)	1.72 × 10−5 (−1.18 × 10−4, 1.52 × 10−4)
probability that a contact made is successfully traced (per 0.1 increase in probability)	−5.43 × 10−3 (−7.27 × 10−3, −3.59 × 10−3)	−5.35 × 10−3 (−7.00 × 10−3, −3.70 × 10−3)	−2.43 × 10−3 (−3.82 × 10−3, −1.05 × 10−3)
mean contact tracing delay (per day)	0.0101 (5.67 × 10−3, 0.0145)	5.49 × 10−3 (1.38 × 10−3, 9.59 × 10−3)	1.40 × 10−3 (−1.97 × 10−3, 4.77 × 10−3)
mean testing delay (per day)	9.42 × 10−3 (5.01 × 10−3, 0.013)	9.71 × 10−3 (6.10 × 10−3, 0.0133)	5.98 × 10−3 (2.38 × 10−3, 9.58 × 10−3)
untraced case identification probability (per 0.1 increase in probability)	−7.79 × 10−3 (−8.72 × 10−3, −6.87 × 10−3)	−0.0110 (−0.0118, −0.0103)	−9.09 × 10−3 (−9.84 × 10−3, −8.33 × 10−3)