Effective in vitro inactivation of SARS-CoV-2 by commercially available mouthwashes

Abstract

Infectious SARS-CoV-2 can be recovered from the oral cavities and saliva of COVID-19 patients with potential implications for disease transmission. Reducing viral load in patient saliva using antiviral mouthwashes may therefore have a role as a control measure in limiting virus spread, particularly in dental settings. Here, the efficacy of SARS-CoV-2 inactivation by seven commercially available mouthwashes with a range of active ingredients were evaluated in vitro. We demonstrate ≥4.1 to ≥5.5 log10 reduction in SARS-CoV-2 titre following a 1 min treatment with commercially available mouthwashes containing 0.01–0.02 % stabilised hypochlorous acid or 0.58 % povidone iodine, and non-specialist mouthwashes with both alcohol-based and alcohol-free formulations designed for home use. In contrast, products containing 1.5 % hydrogen peroxide or 0.2 % chlorhexidine gluconate were ineffective against SARS-CoV-2 in these tests. This study contributes to the growing body of evidence surrounding virucidal efficacy of mouthwashes/oral rinses against SARS-CoV-2, and has important applications in reducing risk associated with aerosol generating procedures in dentistry and potentially for infection control more widely.

Antiviral effect of mouthwashes against SARS-COV-2: A systematic review

“…The final studies included 16 in vitro studies ( Anderson et al, 2020 , Bidra et al, 2020b , Bidra et al, 2020a , Davies et al, 2021 , Hassandarvish et al, 2020 , Jain et al, 2021 , Koch-Heier et al, 2021 , Komine et al, 2021 , Meister et al, 2020 , Muñoz-Basagoiti et al, 2021 , Pelletier et al, 2021 ; C. A. Santos et al, 2021; P .…”

“… Xu et al, 2021 ( Xu et al, 2021 ) USA_WA1/2020 strain(USA) n = 2 Group 1:20-30% ethanol, essential oils – Listerine Antiseptic originalGroup 2: CHX 0.12% – Chlorhexidine gluconate Xttrium LaboratoriesGroup 3: H 2 O 2 1.5% – Colgate PeroxylGroup 4: PVP-I 10% (1% available iodine) – PVP-I CVS Pharmacy 30 min Plaque assay:measure of fluorescence intensity Group 1:20-30% ethanol, essential oils50% (v/v): complete inactivation (relative light unitsx10 4 )5% (v/v): moderate antiviral effect (relative light unitsx10 4 )Group 2: CHX 0.12%50% (v/v): complete inactivation (relative light unitsx10 4 )5% (v/v): moderate antiviral effect (relative light unitsx10 4 )Group 3: H 2 O 2 1.5%50% (v/v): complete inactivation (relative light unitsx10 4 )5% (v/v): complete inactivation (relative light unitsx10 4 )Group 4: PVP-I 10% (1% available iodine)5% (v/v): complete inactivation (relative light unitsx10 4 ) 0.5% (v/v): no inactivation All mouthwashes inactivated the SARS-CoV2 without prolonged incubation. Davies et al, 2021 ( Davies et al, 2021 ) England 2 strain(UK) n = 3 Group 1: CHX 0.2% – Chlorhexidine Gluconate Antiseptic Mouthwash (with ethanol)Group 2: CHX 0.2% – Corsodyl (alcohol free)Group 3: dipotassium oxalate 1.4% – Listerine Advanced Defence Sensitive (alcohol free)Group 4: essential oils, sodium fluoride, zinc fluoride – Listerine Total CareGroup 5: stabilized hypochlorous acid 0.01–0.02% – OraWize+Group 6: H 2 O 2 1.5% – PeroxylGroup 7: PVP-I 0.58% – Povident 1 min Quantitative suspension test: tissue culture infective dose (TCID50/mL) Tissue culture fluid unconcentratedGroup 1: CHX 0.2% (with ethanol)log10 reduction: 0.5 (0.1–0.9)Group 2: CHX 0.2% (alcohol free)log10 reduction: 0.2 (-0.2–0.7)Group 3: dipotassium oxalate 1.4% (alcohol free)log10 reduction: ≥3.5 (3.2–3.8)Group 4: essential oils, sodium fluoride, zinc fluoridelog10 reduction: ≥4.1 (3.8–4.4)Group 5: stabilized hypochlorous acid 0.01–0.02%log10 reduction: ≥5.5 (5.2–5.8)Group 6: H 2 O 2 1.5%log10 reduction: 0.2 (-0.1–0.5)Group 7: PVP-I 0.58%log10 reduction: ≥4.1 (3.8–4.4)Tissue culture fluid concentratedGroup 3: dipotassium oxalate 1.4% (alcohol free)log10 reduction: ≥4.2 (3.9–4.4)Group 4: essential oils, sodium fluoride, zinc fluoridelog10 reduction: ≥5.2 (4.9–5.4)Group 5: stabilized hypochlorous acid 0.01–0.02%log10 reduction: 0.4 (0.0–0.8)Group 7: PVP-I 0.58%log10 reduction: ≥5.2 (4.9–5.4) Mouthwashes with 0,01-0,02% stabilized hypochlorous acid, 0.58% PVP-I, and both alcohol-based and non-alcohol-based products (both Listerine) were effective against the SARS-CoV-2 in vitro .H 2 O 2 1.5% and 0.2% CHX were ineffective against the SARS-CoV-2 in vitro . Munoz-Basagoiti et al, 2021( Muñoz-Bas...…”

“…Santos et al, 2021; P . S. da S. Santos et al, 2021 ) APD 30 sec, 1 min, 5 min, 30 min High effect High effect in vitro Chlorine dioxide Clinical study 1 ( Avhad et al, 2020 ) (Unclear risk) Chlorine dioxide 0.1% 10 mL3 times a day More effective than CHX Variable effect in patients Dequalinium chloride In vitro study 1 ( Meister et al, 2020 ) Dequalinium chloride 1.5mg, benzalkonium chloride 3.5mg 30 sec High effect High effect in vitro Polyaminopropyl biguanide In vitro study 1 ( Meister et al, 2020 ) Polyaminopropyl biguanide (polyhexanide) 0,1 - < 0,25 % 30 sec Moderate to high effect Moderate to high effect in vitro Ethanol + ethyl lauroyl arginate In vitro study 1 ( Statkute et al, 2020 ) Ethanol 23%, ethyl lauroyl arginate 0.147% 30 sec High effect High effect in vitro Delmopinol In vitro study 1 ( Komine et al, 2021 ) Delmopinol 0.20% mouthwash 30 sec High effect High effect in vitro Dipotassium oxalate In vitro study 1 ( Davies et al, 2021 ) Dipotassium oxalate 1.4% 1 min High effect High effect in vitro Stabilized hypochlorous acid In vitro study 1 ( Davies et al, 2021 ) Stabilized hypochlorous acid 0.01–0.02% 1 min Variable effect Variable effect in vitro CDCM (β-cyclodextrin-citrox) Clinical study 1 (Florence Carrouel et al, 2021a ) (Low risk) ...…”

“…Regarding the in vitro studies, H 2 O 2 showed mostly minimal to no effect ( Bidra et al, 2020a , Davies et al, 2021 , Koch-Heier et al, 2021 ), suggesting it might not be that effective against SARS-CoV-2. CHX showed inconsistent results, with some studies finding a strong ( Jain et al, 2021 , Xu et al, 2021 ), weak ( Komine et al, 2021 , Statkute et al, 2020 , Steinhauer et al, 2021 ), or even no ( Davies et al, 2021 , Koch-Heier et al, 2021 ) effect against different strains of SARS-CoV-2. It is possible that both H 2 O 2 and CHX alone are not that effective as mouthwashes, as these in vitro results were mostly negative.…”

Alcohol-based hand sanitizer – composition, proper use and precautions

“…10 Moreover, products containing chlorhexidine gluconate, a nonalcoholic substance as the main ingredient, do not show sufficient activity against SARS-CoV-2. [11][12] Similarly, hydrogen peroxide alone at concentrations of 1.5% and 3.0% has been found to show suboptimal viricidal activity against SARS-CoV-2 while povidone-iodine at concentration of 0.5% completely inactivated SARS-CoV-2 in vitro. 13 ABHS are among the most effective hand sanitizers due to their rapid antimicrobial efficacy, convenience and good tolerance on the skin.…”