Contrary to previous study findings, closing the toilet lid before flushing doesn’t stop aerosolized viruses from contaminating bathroom surfaces, scientists from the University of Arizona and Reckitt Benckiser LLC, the company that makes the disinfectant used in the study, report in the American Journal of Infection Control.

The researchers added a bacteriophage (virus that targets and kills bacteria) to household and public toilet bowls as a proxy for human intestinal viruses. After they flushed the toilets (with the lid open or closed in case of the household toilets), they measured viral contamination of the toilet and bathroom floor and walls.

“Research has demonstrated that people with COVID-19, even those who are asymptomatic, excrete severe acute respiratory syndrome coronavirus (SARS-CoV-2) in fecal matter and other excretions,” the researchers wrote. “Viruses contaminating urine and feces can be aerosolized in building restrooms during toilet flushing.”

The resulting toilet aerosol plumes, they said, can land on surfaces more than 5 feet away.

  • redfellow
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    11 months ago

    Mythbusters busted this myth long before studies. Turns out that air pressure is enough to push the particles flying from the bowl despite the lid, because the toilet lid isn’t a good air tight seal, and the air is pushed out due to water volume increase.

    So basically closing the lid doesn’t help.

    • @[email protected]
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      11 months ago

      Ok it doesn’t 100 percent stop it or it doesn’t help at all? Because I always assumed something as small as a poop bacteria could get through the little cracks but I also assumed having it go through the cracks was better than having it go through the massive entire open bowl where it seemed like more would spray out. Did they comparison test the amount of bacteria on surfaces or just prove that some gets through?

      Edit: obviously I could be wrong but it also seems like having the lid down would direct more bacteria to lower surfaces whereas having it open would give an easier path to higher surfaces where we tend to keep things like toothbrushes.

      • @Pretzilla
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        611 months ago

        Probably depends on the amount of air pressure generated. Then any throttled venturi opening will increase the velocity through it.

        Which is to say, closing the lid could make it shoot farther through the opening.

        But that would also direct it horizontally vs vertically, which is probably preferred.

      • redfellow
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        411 months ago

        Tldr; Control toothbrush contained 98% bacteria or close enough. Make of that what you will. Basically, close your tootbrush in the cupboard.

    • Pelicanen
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      1111 months ago

      Didn’t Mythbusters just prove that the particular kind(s) of fecal bacteria they checked for are present everywhere at all times?

    • @Perhapsjustsniffit
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      711 months ago

      It helps me not drop my toothbrush in there in our tiny bathroom though.