Evaluation of hospital-grade disinfectants on viral deposition on surfaces after toilet flushing

Background: Past studies have shown that infectious aerosols created during toilet flushing result in surface contamination of the restroom. The goals of this study were to quantify viral contamination of surfaces in restrooms after flushing and the impact of disinfectants added to the toilet bowl prior to flushing on reducing surface contamination. Methods: The degree of contamination of surfaces in the restroom was assessed with and without the addition of coliphage MS2 to the toilet bowl before flushing. The bowl water and various surfaces in the restroom were subsequently tested for the presence of the virus. Results: The toilet bowl rim, toilet seat top, and toilet seat underside were contaminated in all trials without a disinfectant added to the bowl water before flushing. All disinfectants significantly reduced concentrations on surfaces when the contact time was ≥15 minutes. Hydrogen peroxide resulted in very little reduction of virus in the toilet bowl (<1 log ₁₀ ). Peracetic acid and quaternary ammonium had the greatest log reductions on virus in the organic matter in the toilet. Conclusions: Toilet flushing resulted in extensive contamination of surfaces within the restroom. Addition of disinfectant to the toilet bowl prior to flushing reduced the level of contamination in the bowl and fomites after flushing.