Fig. 5.

Transmission and intervention of COVID-19 in the U.S.; The boxes denote mitigation measures, and the circles depict the disease evolution. Transmission starts from viral shedding by asymptomatic and symptomatic carriers and occurs via the contact and airborne routes. Social distancing, in conjunction with hand sanitizing, minimizes contact transmission, rendering airborne transmission as the most likely route. The remnants after the combined social distancing and face covering (dashed line) account for possible virus transmission due to circumstances when excising the measure is not possible or the measure is disobeyed and/or due to imperfection of the measure. The combined face covering and social distancing measures with rapid and extensive testing as well as contact tracing is key to curbing the COVID-19 pandemic.