Download This PaperHypothiocyanite for the Prevention and Control of COVID-19
10 Pages Posted: 4 May 2020
Date Written: April 18, 2020
Abstract
Unlike SARS-CoV, SARS-CoV-2 seems to replicate efficiently in the upper airways during the incubation period, which is estimated to last up to 14 days. During this prodromal stage, asymptomatic individuals release large amounts of viruses from infected cells. Therefore, there are two health problems with COVID-19: transmissibility of the virus and infection.
The lactoperoxidase (LPO), an enzyme present in several exocrine secretions, including the interface of the humans’ airways epithelium, produces different anti-infectious reagents, principally from halide and pseudo-halide substrates. The hypothiocyanite ion (OSCN−), one of the products of the LPO/H2O2/SCN− extracellular oxidative complex, is part of the human natural protective system of central airways against pathogen threats.
At micromolar concentration, the reactive mixture LPO/H2O2/OSCN− proved cidal activity against a range of bacteria (Gram positive and negative), fungi (Candida albicans and Candida krusei) and viruses as HIV, herpes-simplex virus (HSV-1), adenovirus, echovirus, respiratory syncytial virus (RSV) and influenza virus.
In a recent experiment in-vitro, OSCN- produced by the oxidase/LPO/thiocyanate system rapidly and effectively inactivated A/swine/Illinois/02860/09 (swH1N2) influenza A virions.
In another recent in-vitro cell-free experiment, all 12 different strains of influenza A and B viruses (the major circulating serotypes and species causing epidemics) were effectively inactivated by the LPO/H2O2/(SCN-/I-) system, with a strain-independent effect.
In another laboratory experiment challenging enzyme free OSCN− against A/H1N1 2009 pandemic influenza virus in-vitro, an evident dose-dependent viricidal activity was observed, with no cell toxicity.
OSCN− seems able to alter the surface proteins of different respiratory viruses, probably by oxidizing free thiol radicals and creating disulfide bonds, thus contrasting the binding of viruses with the human airways mucosae. OSCN- may also arguably hamper the synthesis and assemblance of viral proteins and nucleic acids, thus interfering with the release of viruses from infected cells. Considering a demonstrated wide spectrum cidal effect, not targeting specific proteins, it could be reasonably argued that OSCN− may be effective also against SARS-CoV-2 and would therefore deserve to be tested in vitro also for the novel coronavirus.
Infection Prevention and Control (IPC) measures against COVID-19 are mainly based upon self-isolation, social distancing, hygiene rules and use of personal protective equipment (PPE). In the event these measures would be insufficient to control the spread of COVID-19 a complementary approach is clearly needed.
If effective against the novel coronavirus, enzyme-free OSCN− could support the current public health measures enforced in several countries to contain the spread of COVID-19, providing multiple potential benefits for the prevention and control of the disease.
Note: Funding: None.
Conflict of Interests: None to declare.
Keywords: coronavirus; COVID-19; SARS-CoV-2; hypothiocyanite; lactoperoxidase; disinfection; in vitro; in vivo
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