Nobody likes vomit. It’s no fun for the person vomiting or the people around when it happens. It’s a sign our body is so uncomfortable — the reason for which could be one of many things — that its last resort in trying to feel better is expelling the contents of the stomach. As if this isn’t all pleasant enough, scientists have discovered that vomit can be much more harmful.

The first direct evidence that vomiting can aerosolize virus particles has come out of a study by researchers at North Carolina State University and Wake Forest University. Epidemiological evidence has suggested that virus aerosolization is a likely route for the spread of norovirus, but the new study confirms that this is not only possible, but probable.

"When one person vomits, the aerosolized virus particles can get into another person's mouth and, if swallowed, can lead to infection," said Lee-Ann Jaykus, a professor of food, bioprocessing, and nutrition sciences at NC State, co-author of a paper on the work, and director of the USDA-NIFA Food Virology Collaborative initiative (NoroCORE). "But those airborne particles could also land on nearby surfaces like tables and door handles, causing environmental contamination. And norovirus can hang around for weeks, so anyone that touches that table and then puts their hand to their mouth could be at risk for infection."

The research team developed their own vomiting device that allowed them to control the volume, viscosity, and pressure of simulated vomiting. They came up with the device so they could have a controlled way to observe and study vomiting repeatedly, something that would be very useful in the study of communicable diseases and their spread.

They contaminated the artificial vomit with a virus called the MS2 bacteriophage — this virus is not harmful to humans but is a commonly used proxy for norovirus. The scientists used the device to determine whether the virus was bioaerosolized during a simulated vomit and found that it absolutely was.

"At most, only 0.02 percent of the total virus in the vomit was aerosolized," Jaykus said. "But that can still amount to thousands of virus particles — more than enough to infect other people."

A future direction for research would include measuring how long virus particles can stay airborne and how far they may be able to travel in the air.

Source: Tung-Thompson G, Libera D, Koch K. Aerosolization of a Human Norovirus Surrogate, Bacteriophage MS2, During Simulated Vomiting. PLOS ONE. 2015.