Aerosolized particles produced while speaking may be enough to transmit coronavirus infection by those who are asymptomatic.
Undetected and undocumented cases of COVID-19 were largely responsible for the rapid spread of the virus in China. 86% of all infections were undocumented before the January 23 Wuhan travel shutdown. Per person, the undocumented infections were half as contagious as documented infections but were the source of two-thirds of documented infections.
The time between cases in a chain of transmission of COVID-19 is less than one week, and more than 10% of patients are infected by someone who has the virus but is not yet symptomatic.
