There's a certain comfort in the toilet seat cover, the tissue-thin layer of grace between your bare behind and a piece of cold, dirty plastic. But what happens if you forgo the cover, boldly plopping down on a surface crawling with who knows what?
Toilet seat covers are absorbent and bacteria and viruses are tiny, able to pass through the relatively large holes in the cover's paper, said Kelly Reynolds, a public health researcher at the University of Arizona. That means they don't stop the spread of germs, she said, but the risk of germ transmission from your skin touching a toilet seat is unlikely in the first place.
Germs will more likely spread after you flush, when bits of fecal matter blast into the air in aerosol form, a phenomenon known as "toilet plume." From there, Reynolds said, the "bits of fecal matter settle on surfaces, contaminate hands and then get spread to the eyes, nose or mouth."
Dr. William Schaffner, a professor of preventative medicine at Vanderbilt University, agreed. He pooh-poohed seat covers to the Huffington Post, which found research has refuted notions that toilet seats spread sexually transmitted infections or gastrointestinal infections.
“That’s because toilet seats are not a vehicle for the transmission of any infectious agents—you won’t catch anything,” Schaffner said.
And covering the seat with toilet paper? That may even make things worse. Placing pieces of toilet paper around the seat as an impromptu cover only increases the surface area for germs to multiply on, as Raymond Martin, a director with the British Toilet Association, told Buzzfeed. That makes it "considerably less hygienic," he said. (And toilet plumes may have blasted fecal matter onto the toilet paper anyway.)
The seat covers can keep things cleaner, however, said Reynolds: They make people more likely to sit on toilets rather than hover over them, reducing general splatter. That makes them a "net benefit," she said.
The biggest risk in public restrooms remains the spread of fecal matter to the mouth, Reynolds said, and that starts with the hands. Just remember to wash your hands, lathering with soap and scrubbing for 20 seconds before rinsing, as the CDC recommends. Then you're truly covered.