Norovirus remains one of the most contagious and resilient viral pathogens known today, responsible for over 685 million cases of gastroenteritis globally each year. Gastroenteritis, a condition that causes inflammation of the stomach and intestines, leads to vomiting and diarrhea. Norovirus is the leading cause of acute gastroenteritis in the United States among all age groups. Traditional alcohol-based hand sanitizers have proven largely ineffective against norovirus. Hypochlorous acid (HOCl), a naturally occurring antimicrobial produced by the human immune system, has emerged as a powerful, non-toxic alternative that is both scientifically validated and safe for high-frequency human use. This paper explores the biochemistry of HOCl, its virucidal efficacy, and why it represents a paradigm shift in infection control—particularly in environments where norovirus risk is high.
1. Introduction
Norovirus, often dubbed the 'winter vomiting bug,' is the leading cause of acute gastroenteritis worldwide. The virus spreads easily by contaminated surfaces, aerosols from vomiting, and hand-to-mouth contact. Known as a non-enveloped virus, Norovirus resists inactivation by most alcohol-based hand sanitizers. As existing health care protocols for virucides favor alcohol-based sanitizers, it highlights a major shortcoming in existing public health hygiene protocols.
While bleach is often the chemical of choice for surface disinfection, its corrosiveness and toxicity make it unsuitable for use on skin. This leaves a critical need for a topically safe, highly effective viracidal agent.
2. The Science of HOCl
Hypochlorous acid (HOCl) is an excellent virucidal alternative to kill Norovirus. HOCl is created naturally within human bodies and produced artificially outside the human body for many different applications.
HOCl has been used for over a century to disinfect hospitals by sanitizing commonly used surfaces, sensitive equipment, and more. The human immune system creates HOCl to kill invading organisms and to defend against infection. Our immune system uses HOCl in the fight against viruses, bacteria, and fungi.
HOCl can be produced outside the body also by running electricity through a saltwater solution - a process known as electrolysis. Be careful. Not all HOCl products are equal. HOCl can differ in their efficacy, shelf life can vary from days to years, and pH ranges can vary drastically making some of them unsuitable for any skin contact.
HOCl is not stable in the presence of oxygen, heat, or direct sunlight. Until recently it was not possible to stabilize HOCl for more than 24 hours. Some bottling techniques can stabilize HOCl products for up to 30 days, however, once a container is opened the HOCl will slowly begin to break down and lose its ability to kill harmful bacteria, viruses, and fungi. Previously, the instability or short shelf-life made HOCl undesirable for general household disinfection and sanitization.
HOCl production requires technical expertise, special handling instructions, expensive equipment, and high-grade raw materials. This has made it generally unavailable for the public’s use. The HOCl industry is changing and new technologies as well as state-of-the-art production processes have made shelf life significantly longer.
Importantly, HOCl is 100x more effective than sodium hypochlorite (NaOCl)—conventional bleach—at equivalent concentrations.
A high quality, world class stabilized HOCl possesses the following attributes:
- Non-corrosive as it contains no harmful chemicals
- Non-toxic and no harsh fumes
- No allergen or asthma triggers
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No rinse required
- Animal safe
- Food surface and contact safe
3. HOCl vs Norovirus: A Proven Match
Numerous peer-reviewed studies and EPA-registered formulations have shown HOCl’s virucidal efficacy against norovirus. Notably:
- In EPA Protocol MB-31, HOCl has demonstrated >99.99% reduction in human norovirus surrogate (feline calicivirus or murine norovirus) within 1 minute of contact time.
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The CDC and WHO acknowledge the limitations of alcohol-based hand rubs in controlling norovirus, particularly in outbreak settings like cruise ships, hospitals, schools, and food service.
Key takeaway: HOCl effectively kills norovirus, whereas alcohol is ineffective in killing norovirus.
4. A Superior Hand Sanitizer
Alcohol-based hand sanitizers are widely used but are ineffective against various viruses, including norovirus, rotavirus, and poliovirus. In contrast:
HOCl is:
- Effective against Norovirus
- Safe for frequent use
- Non-flammable
- Use around food
- Eye/mouth safe
*GRAS = Generally Recognized As Safe by the FDA.
HOCl can be used without gloves, around food handlers, in daycare environments, and by vulnerable populations—without compromising efficacy or safety.
5. Applications in High-Risk Settings
- Healthcare: Pre/post-contact disinfection, hand hygiene without risk of skin degradation.
- Education: Safe for children, effective during seasonal outbreaks
- Food Service: Dual use as surface & hand sanitizer, non-tainting.
- Cruise ships/prisons/military: Close-quarters living requires robust, skin-safe solutions.
6. Regulatory Support & Market Adoption
- EPA Registered: Multiple HOCl formulations are approved as List G disinfectants for use against norovirus.
- FDA Approved for skin: When produced within defined parameters, HOCl is cleared for topical application on skin, wounds, and mucous membranes.
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NSF certified: HOCl has been certified for no-rinse use on food-contact surfaces.
Major organizations such as the U.S. Department of Defense, VA hospitals, and WHO field hospitals have deployed HOCl-based systems during outbreaks and crises, including COVID-19.
7. Conclusion
Hypochlorous acid is a natural, safe, and scientifically superior solution for disinfection, particularly against tough pathogens like norovirus. Unlike alcohol-based sanitizers, HOCl works where it counts—destroying the most resilient viruses without harming the user. As outbreaks of gastrointestinal illness continue to challenge public health infrastructure, HOCl offers a sustainable, accessible, and effective line of defense.
References
- CDC Guidelines for Norovirus Outbreak Management
- CDC Norovirus Facts and Stats
- Block, S.S. (Disinfection, Sterilization, and Preservation. 5th ed.)
- "Virucidal efficacy of hypochlorous acid against norovirus surrogates", Journal of Applied Microbiology
- FDA GRAS Notice for Electrolyzed Water HOCl