Using data on 40,162 individuals from the BBC Pandemic dataset (collected in 2017-2018 with data on recorded social contacts of each participant), Kucharski et al mathematically modeled individual-level SARS-CoV-2 transmission stratified by setting (household, work, school, or other) to compare the effects of combinations of testing, isolation, contact tracing, and physical distancing on reducing secondary cases. The authors found that in the absence of other measures, achieving an effective R of less than 1 required a high proportion of cases to self-isolate and a high level of successful contact tracing, with a 64% reduction for self-isolation and household quarantine plus manual contact tracing of all contacts. Combining testing and tracing was more effective than both mass testing or selfisolation alone. Depending on the effectiveness of testing, isolating, and contact tracing, adding physical distancing measures to the combined strategy of self-isolation and contact tracing may be required to achieve an effective R lower than 1. The authors also suggest that manual contact tracing (i.e. people who have been met before) may be as effective as detailed contact tracing in circumstances where gatherings outside of home, school, or work are restricted.