During the SARS outbreak in China, a handful of “super spreaders” may have transmitted the airborne disease much better than others. Supporting this idea, a group led by Harvard University researchers measured the number of microscopic fluid droplets exhaled from 11 healthy subjects and found that just six of them breathed out 98 percent of the droplets. The researchers then had the subjects inhale nebulized saline for a few minutes. The saline treatment cut the number of droplets by 66 to 80 percent for up to six hours, probably by increasing the surface tension of the mucosal linings of the lungs and thereby preventing smaller (and more easily exhaled) droplets from forming. A saline spray could reduce the spread of airborne diseases, including SARS, tuberculosis and influenza, the investigators suggest in the December 14, 2004, Proceedings of the National Academy of Sciences USA.
This article was originally published with the title "Say It, Don't Spray It" in Scientific American 292, 2, 32 (February 2005)