Before revision:  Modeling results show that a 50\\% adoption rate of Social distancing 2.0, with privacy-preserving contact tracing, would suffice to decrease the R_0 to less than 1 and prevent the resurgence of COVID-19 epidemic.
After revision:  Modelling results show that a 50\\% adoption rate of Social distancing 2.0, with privacy-preserving contact tracing, would suffice to decrease the R_0 to less than 1 and prevent the resurgence of COVID-19 epidemic.