The effectiveness of various gargle formulations and salt water against SARS-CoV-2

Abstract

The COVID-19 is difficult to contain due to its high transmissibility rate and a long incubation period of 5 to 14 days. Moreover, more than half of the infected patients were young and asymptomatic. Virus transmission through asymptomatic patients is a major challenge to disease containment. Due to limited treatment options, preventive measures play major role in controlling the disease spread. Gargling with antiseptic formulation may have potential role in eliminating the virus in the throat. Four commercially available mouthwash/gargle formulations were tested for virucidal activity against SARS-CoV-2 in both clean (0.3 g/l BSA) and dirty (0.3 g/l BSA + 3 mL/L human erythrocytes) conditions at time points 30 and 60 s. The virus was isolated and propagated in Vero E6 cells. The cytotoxicity of the products to the Vero E6 was evaluated by kill time assay based on the European Standard EN14476:2013/FprA1:2015 protocol. Virus titres were calculated as 50% tissue culture infectious dose (TCID50/mL) using the Spearman-Karber method. A reduction in virus titer of 4 log10 corresponds to an inactivation of ≥ 99.99%. Formulations with cetylperidinium chloride, chlorhexidine and hexitidine achieved > 4 log10 reduction in viral titres when exposed within 30 s under both clean and dirty conditions. Thymol formulations achieved only 0.5 log10 reduction in viral titres. In addition, salt water was not proven effective. Gargle formulations with cetylperidinium chloride, chlorhexidine and hexetidine have great potential in reducing SAR-CoV-2 at the source of entry into the body, thus minimizing risk of transmission of COVID-19.

Cetylpyridinium chloride promotes disaggregation of SARS-CoV-2 virus-like particles

“…These effects were confirmed by electron microscopy. In addition, analogous experiments using CPC diluted in filtered saliva showed similar antiviral results [ 40 ]. Future experiments will discern if the addition of compounds like CPC to mouthwashes is a valid strategy to fight against other enveloped virus, such as other coronaviruses [ 7 ].…”

Oral Antiseptics against SARS-CoV-2: A Literature Review

“…Coughing once or having a five-minute conversation can produce up to 3000 droplets of saliva, whereas a sneeze can produce up to 40,000 droplets [ 18 ]. It has recently been shown that mouthwashes can rapidly inactivate SARS-CoV-2 through in vitro [ 2 , 16 , 19 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ] and in vivo studies [ 3 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. Subsequently, there have been extensive discussions regarding the utilization of mouth rinses to possibly complement current prevention measures such as facemasks, hand disinfection, and social distancing in order to reduce the global spread of SARS-CoV-2 [ 18 ].…”

“…Additionally, Koch-Heier et al, evaluated two rinses—ViruProX® (0.05% CPC and 1.5% H 2 O 2 ) and BacterX® (0.1% CHX, 0.05% CPC, and 0.005% fluoride)—and their results showed that 0.1% CHX and 1.5% H 2 O 2 present in the rinses did not exhibit a reduction in viral load, although 0.05% CPC present in both rinses was responsible for the virucidal effect against SARS-CoV-2, which significantly reduced the viral load [ 24 ] ( Table 1 ). Tiong et al found that CPC was able to decrease around 99.99% of the concentration of SARS-CoV-2 after 30 s of exposure, exhibiting a slightly higher virucidal activity than CHX [ 26 ] ( Table 1 ).…”

Recommendation of the German Society of Hospital Hygiene (DGKH): Prevention of COVID-19 by virucidal gargling and virucidal nasal spray – updated version April 2022

“…Consistently, CHG was also ineffective in the oral cavity [ 35 ]. Studies in which CHG had been found to be effective [ 36 ] were apparently based on incomplete neutralization of CHG adsorbed to virus and only simulated efficacy. Results differ for stabilized hypochlorite [ 32 ].…”

“…Gargling with hypertonic saline (2%–3%) 3 times/d significantly shortened the duration of illness from viral influenza, with the reduction in viral shedding reducing the incidence of illness by 35%, even among people living in the same household. Since saline is not virucidal in vitro [ 36 ], hypochlorite is probably formed intracellularly due to the increased chlorite availability; it is also possible that viral adherence is reduced.…”