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In order to eliminate the pandemic of the new crown epidemic, it is necessary to block or reduce the spread of the SARS-CoV-2 virus in the population. Studies have shown that COVID-19 patients have a higher viral load in the early stage of onset, and their viral load change pattern is different from SARS virus and more similar to influenza virus. It also suggests that COVID-19 patients may begin to spread early in onset Virus.
Initially, the highest viral load appeared in the upper respiratory tract of confirmed patients. The World Health Organization (WHO) guidelines recommend covering the nose and mouth, maintaining social distancing, and maintaining good breathing and hand hygiene. Therefore, any measures that can reduce the viral load of the nasal cavity are likely to minimize the probability of disease transmission.
Nasal sprays for the treatment of respiratory viruses have been explored in preclinical and other trials. Many potential COVID-19 nasal spray therapeutic products have been explored. In nasal preparations, it shows good bactericidal and antiviral effects.
On February 11, 2021, Michelle Mendenhall of Utah State University in the United States and others studied the in vitro killing effect of a high-purity spray containing stable hypochlorous acid (HClO) on human SARS-Cov-2 coronavirus, and The tolerance of the nasal cavity and oral mucosa provides a possible solution for upper respiratory tract hygiene.
The hypochlorous acid virus killing test showed that the virus titer and log reduction value (LRV) of SARS-CoV-2 are shown in the following table:
LRV: log reduction value log reduction value
The test results showed that the virus titer of SARS-CoV-2 was reduced from 3.5 logCCID50/mL to 0.7logCCID50/mL within the test time of <1min and 3min, and the virus killing rate reached 99.8%.
At the same time, the oral mucosa and nasal mucosa tolerance test results showed that the hypochlorous acid water experimental group and the control group did not observe any clinical symptoms or death, and no local abnormal reactions were observed in the nasal cavity and oral mucosa. The irritation index was evaluated on histological samples of oral tissues and determined to be 0.0, indicating that the hypochlorous acid aqueous solution has no irritation to the cheek tissues of golden Syrian hamsters.
After using hypochlorous acid water to treat the nasal cavity for 5 consecutive days, all the tested animals showed no pathological reactions. In the 0.2ml and 0.5ml dose groups, the histological irritation index of the nasal mucosa was 0 and 0.083, respectively, indicating that hypochlorous acid water had no irritation to the nasal mucosa of male New Zealand white rabbits.
This study confirmed the antiviral effect of hypochlorous acid water on SARS-Cov-2 and its high tolerance to nasal and oral mucosa. To be supported by further clinical trials, hypochlorous acid water as a nasal spray has great potential application value against SARS-Cov-2 virus.
