Before revision:  We also show that, when the number of traced contacts is small, the number of prevented transmission per traced node is even higher---although most traced individuals are healthy---than that from case isolation without contact tracing .
After revision:  We also show that, when the number of traced contacts is small, the number of prevented transmissions per isolation---case isolation combined with a small amount of contact tracing is more efficient than case isolation alone. By demonstrating that backward contact tracing is highly effective at discovering super-spreading events, we argue that the potential effectiveness of contact tracing has been underestimated. Therefore, there is a critical need for revisiting current contact tracing strategies so that they leverage all forms of biases.