Before revision:  We agree with Zhang et al. that masks can be an important element in reducing virus transmission and that widespread use may be essential for returning to full activity. However, their analysis neglects the potential importance of physical distancing for limiting COVID-19 transmission by misattributing its effect to mask requirements. A full suite of epidemiological tools is necessary in these challenging times .
After revision:  We agree with Zhang et al. 's analysis that their method is flawed .