The surgeon needs to have an inexpensive, available, nontoxic, and practical disinfectant that is effective in sanitizing against the COVID-19 (Coronavirus Disease 2019) virus. The purpose of this article was to review the evidence for using hypochlorous acid in the office setting on a daily basis. The method used to assemble recommendations was a review of the literature including evidence for this solution when used in different locations and industries other than the oral-maxillofacial clinic facility. The results indicate that this material can be used with a high predictability for disinfecting against the COVID-19 (Coronavirus Disease 2019) virus.
Go to:COVID-19 (Coronavirus Disease 2019) Virus Structure and Mechanism of InfectionCoronavirus Disease 2019 (COVID-19) is a novel virus. It causes severe acute respiratory syndrome. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the agent responsible for a surface-to-surface communicable disease that had infected approximately 4.7 million persons as of May 17, 2020.1 Health care providers need options to limit and control the spread of the virus between themselves and patients.
COVID-19 is an enveloped, positive-sense, single-stranded RNA virus approximately 60 to 140 nm in diameter. The virus's Spike glycoprotein S1 firmly binds to the angiotensin converting enzyme 2 (ACE2) receptor, which allows entry into the host cell.2, 3, 4 COVID-19 infection creates a cytokine storm, severe pneumonia, multiple-organ failure, and acute cardiac injury.5 , 6
Transmission occurs through touch or aerosol spreading of the virus. A common pathway of spreading this virus is through respiratory aerosols from an infected person.7 During speech, humans emit thousands of oral fluid droplets per second that can remain airborne for 8 to 14 minutes.8 COVID-19 is detectable for up to 3 hours in surface aerosols, for up to 4 hours on copper, for up to 24 hours on cardboard, and for up to 2 to 3 days on plastic and stainless steel.9 , 10 There is a need to disinfect surfaces potentially exposed to COVID-19 to prevent transmission.
Go to:Use of DisinfectantsOn contact with the virus, a disinfectant agent changes the protective protein coat, which loses its structure and aggregates, forming clumps of proteins with other viruses.9 , 10 Currently, the US Environmental Protection Agency has recommended numerous disinfectants against COVID-19 including hypochlorous acid (HOCl).11 The mechanism of disinfection involves the destroying of the cell wall of microbes or viruses, allowing the disinfectant to destroy or inactivate them.12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27 This article focuses on HOCl.
Go to:Hypochlorous AcidAn ideal disinfectant and sanitizer must be nontoxic to surface contact, noncorrosive, effective in various forms, and relatively inexpensive. HOCl may be the disinfectant of choice for coronaviruses in an oral-maxillofacial surgery (OMS) office.
HOCl is an endogenous substance in all mammals and is effective against a broad range of microorganisms. Neutrophils, eosinophils, mononuclear phagocytes, and B lymphocytes produce HOCl in response to injury and infection through the mitochondrial membrane–bound enzyme known as “respiratory burst nicotinamide adenine dinucleotide phosphate oxidase.”28 HOCl selectively binds with the unsaturated lipid layer and subsequently disrupts cellular integrity. Between pH levels of 3 and 6, the predominant species is HOCl that has maximal antimicrobial properties.29 , 30
HOCl is a powerful oxidizing agent. In aqueous solution, it dissociates into H+ and OCl–, denaturing and aggregating proteins.30 HOCl also destroys viruses by chlorination by forming chloramines and nitrogen-centered radicals, resulting in single- as well as double-stranded DNA breaks, rendering the nucleic acid useless and the virus harmless.31
How Is HOCl Made?HOCl can be made on-site combining non-iodinated salt, water, and electrolysis. The system to make HOCl on-site is a 1-L container that is filled with water, to which 1 g of non-iodized salt and 1 teaspoon of vinegar are added. The system has the ability to make concentrations of 50 to 200 ppm (in which 1 ppm is equal to 1 mg/L) depending on its use, which is chosen by pressing a button on the instrument. The electrolyzed solution is completed in 8 minutes, when it is ready for use.
The parameters that contribute to HOCl's efficacy as a disinfectant include contact time and concentration.32, 33, 34 The method of application also will affect its efficacy to disinfect.
Stability of SolutionRossi-Fedele et al35 investigated the shelf life of HOCl by being either exposed to or protected from sunlight. When the HOCl solution was exposed to sunlight, the chlorine reduction started on day 4. When it was sheltered from sunlight, the chlorine reduction started after day 14. The half-life increases with decreasing pH owing to the decreasing ratio of OCl–to HOCl.36 The parts per million (ppm) is the concentration of the –OCl, which is the active ingredient and is known as the available free chlorine (AFC) in the solution. HOCl solutions are less stable when exposed to UV radiation, sunlight, or contact with air or when the temperature of the solution is elevated greater than 25°C. HOCl solutions should be stored in cool, dark places, and contact with air should be minimized. The water for fabrication should be water that contains organic and inorganic ion concentrations that are as small as possible.37, 38, 39, 40
Concentration Related to Time Needed for Virucidal ActionHOCl has been shown to inactivate a variety of viruses including coronaviruses in less than 1 minute.39 At a concentration of 200 ppm, HOCl is effective in decontaminating inert surfaces carrying noroviruses and other enteric viruses in a 1-minute contact time. When diluted 10-fold, HOCl solutions at 20 ppm were still effective in decontaminating environmental surfaces carrying viruses in a 10-minute contact time.40
Go to:Recommendations for Office Use