It may sound like something right out of a file labelled weird science, but researchers have developed a machine that pukes on command to test their theory that viruses are aerosolized during vomiting. The study, published in the Aug. 19 issue of PLOS ONE, provides the first direct evidence that vomiting does indeed spread virus particles.
“We have suspected aerosolization of virus in vomiting for probably 20 years, but we never provided any kind of laboratory-based proof of it,” study author Lee Ann Jaykus, professor of food science at North Carolina State University, told TIME.
Recruiting students to vomit virus particles in a lab was clearly not a solution, so Jaykus asked colleague Francis de Los Reyes III, a professor of civil, construction and environmental engineering at NC State, to design a machine that simulates vomiting. The end result was a plexiglass box that contained a scaled-down esophagus/stomach system attached to a small face that mimics human vomiting by upchucking vanilla pudding at a velocity, volume and viscosity that matches the real thing.
To determine if the virus was present in the fake vomit, the researchers contaminated the vanilla pudding with the virus MS2 bacteriophage – a commonly-used proxy for norovirus that does not make humans sick. Jaykus and her team also wanted to know how much became airborne if the virus was aerosolized.
The research team found that just 0.02 percent of the virus becomes aerosolized. A seemingly small amount, but more than enough to spread norovirus, which according to the Centers for Disease Control and Prevention (CDC), causes 20 million infections a year. Even the lowest levels of aerosolization would launch 13,000 particles into the air, and it takes only 20 to 1,300 to make a person sick.
“When one person vomits, the aerolsolized particles can get into another person’s mouth and, if swallowed, can lead to infection,” Jaykus said in a news release.
“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 who touches that table then puts their hand to their mouth, could be at risk for infection,” Jaykus added.
Norovirus symptoms include stomach pain, vomiting and diarrhea and contribute to 56,000 to 71,000 hospitalizations annually. The virus is also responsible for up to 800 deaths yearly in the U.S. Close contact is a major norovirus risk factor, and it is known to be easily passed from person to person in healthcare facilities, nursing homes, catered events, cruise ships, hotels and schools.
Because norovirus can live for so long on surfaces, health officials advise using bleach where possible to clean up vomit. And frequent handwashing is essential.
If you are near someone who vomits, Jaykus recommends that the “safest thing for you to do would be to walk away. The further you get from the aerosol, probably the better off you are.”