By now you likely know the basics of preventing the spread of COVID-19. But a bathroom that’s public or shared outside of your own home is a unique environment in a few ways—and experts are increasingly interested in the potential for bathrooms to fuel transmission of the coronavirus.
What makes shared restrooms different? For one thing, a bathroom is usually a small enclosed space that’s not well ventilated, which we know makes it easier for the coronavirus to spread. Second, we’re talking about bathrooms you share with people that you don’t live with, which means you’re being potentially exposed to new sources of COVID-19 thanks to shared surfaces that may or may not be sanitized regularly.
And, finally, there’s the toilet plume, which is the term used to describe what happens after you flush the toilet: The force of the flushing causes tiny particles of everything in the toilet—pee, poop, whatever—to spray into the air, SELF explained previously. This is worrying because some diseases (such as norovirus and Claustridium difficile) are known to spread via fecal transmission, so having more of that matter in the air could make it more likely for those illnesses to spread. So far, research suggests that toilet plume could play a role in the transmission of these diseases, but that idea hasn’t been conclusively proven.
Still, the idea of COVID-19 in a bathroom possibly spreading via toilet plume is definitely concerning. We do have research to suggest that particles of the coronavirus are present in feces and that, under the right circumstances, short-range airborne transmission of the virus is possible.
Additionally, researchers published a study in June in Physics of Fluid that demonstrated the potential for COVID-19 particles in toilets to spread above the toilet seat after flushing. For this study, the researchers created simulations of the movement of viral particles in response to flushing two different types of toilets. Their simulations showed that as much as 40% to 60% of the viral particles rose above the toilet seat after flushing, including some particles that went up to three and a half feet in the air. Even in the 35 to 70 seconds after flushing, the particles continued to rise, the researchers say. However, this was just a simulation and isn’t a guarantee that viral particles will behave exactly like this in a real-world scenario. This study also doesn’t prove that this type of toilet plume can actually make someone sick.
Just this week, researchers also found that even urinals could produce aerosolized particles. (Yes, particles of the SARS-CoV-2 virus that causes COVID-19 have been found in urine, too.) For this study, which was also published in Physics of Fluid, researchers used the same type of model that the toilet flushing researchers used to examine the potential for viral particles in urine to float upwards after flushing a urinal. Their results “suggest that an alarming upward flow with strong turbulence can be generated,” the authors write. But again, this is a simulation and not an observation of what actually happens in real life.
We don’t have conclusive evidence that toilet plume could actually result in coronavirus transmission or that coming into contact with the particles produced by toilet plume could actually make you sick. But if you’re worried about it, one easy thing you can do is close the toilet lid when you flush if you’re not already doing that. (And experts generally advise doing so anyway.)
Also, wearing a mask in a public restroom seems like a pretty good idea, which you’re hopefully doing any time you’re in a public place already. In fact, this is something that experts have recommended to SELF in the past, especially for those who are not working at home right now or traveling and may need to use a shared or public restroom.