Figure 6
Empirical estimated impact of mask usage in King County, Washington. Regression model estimates of reduction in effective reproductive number (Re) explained by human mobility and mask wearing. (A) Percent of devices at home above baseline using smoothed Google mobility data between March and August 2020. (B) From the greater Seattle Coronavirus Assessment Network (SCAN), fraction self-reporting they always wear a mask when in public. Data and best fit line with associated 95% confidence interval (CI). (C) Estimated Re from epidemiological data (red), modeled reduction in Re due to reduced mobility and masking (solid black), and counterfactual scenario without masks (dashed black). Each line is bounded by 95% CI. Dates marking important events and local policy changes that affected gathering behavior and masking are overlaid.
