Which disinfectant is most effective for decontaminating surfaces affected by human norovirus?

• A. Alcohol-based sanitizers
• B. Quaternary ammonium products
• C. Bleach
• D. Water

Answer: (C)

Norovirus is a non-enveloped virus, which makes it more resistant to many sanitizers. Among common disinfectants, chlorine bleach is reliably effective against it when used correctly. Alcohol-based sanitizers and quaternary ammonium products don’t consistently inactivate non-enveloped viruses like norovirus, especially in the presence of organic material, whereas bleach works through its strong oxidizing action. Water is not a disinfectant, so it won’t inactivate the virus. To properly decontaminate affected surfaces, pre-clean to remove soil, then apply a fresh chlorine bleach solution at the recommended concentration (for example, a 0.1% available chlorine solution, typically made by diluting household bleach) and keep the surface wet for the required contact time (often several minutes). Afterward, rinse or allow to air dry as directed and follow safety precautions.