Although scientists have not yet fully identified the transmission mechanisms of the COVID-19 virus, current research indicates that people without symptoms could infect others through tiny droplets created when they speak, sing or laugh. Stone and co-lead researcher Manouk Abkarian, of the University of Montpellier in France, wanted to learn how widely and quickly exhaled material from an average speaker could spread in an interior space. “Lots of people have written about coughs and sneezes and the kinds of things you worry about with the flu,” Stone said. “But those features are associated with visible symptoms, and with this disease we are seeing a lot of spread by people without symptoms.”  To read the full story.