Studying Violent Expiratory Events (aka Sneezes)

One of the most important tools in the fight against the spread of infectious disease is understanding how germs are spread from person to person. That’s why Lydia Bourouiba, a researcher at the Massachusetts Institute of Technology (MIT) in Cambridge dedicates a great deal of her time and work to mapping out the dynamics of the sneeze. With the help of a sophisticated video camera that records over a thousand frames per second, Dr. Bourouiba and a team of researchers carefully analyzed the trajectory of all that saliva and mucus that we expel when we let out a big sneeze. The results are gross, surprising, and quite insightful. As it turns out, all those germ-filled particles travel quite a bit further than you might think.

Violent expiratory events

Studying coughing and sneezing is especially important when it comes to understanding the spread of infection because the two bodily functions are, as Bourouiba puts it, violent expiratory events. In other words, the two send germs propelling through the air in a manner that facilitates the airborne spread of disease. Apart from these two events, the options that germs have for traveling from person to person are much more limited—they would basically necessitate direct contact.

So just how far can airborne germs travel?

The traditional line of thought assumed that a sneeze would propel airborne germs one—maybe two—meters. As the video studies mentioned above ultimately proved, however, the true reach of a sneeze is much greater. The truth of the matter is that sneezes can propel droplets of mucus and saliva up to eight meters—and the moisture from these “expiratory events” can remain suspended in the air for over ten minutes! This has serious ramifications for the ways that healthcare workers will think about protecting themselves and their patients from infected individuals.

For more information on what bacteria and viruses might be in your sneezes, simply visit our blog at CosmosID—what you learn may surprise you!