Virucidal activity of CPC-containing oral rinses against SARS-CoV-2 variants and are active in the presence of human saliva

Abstract

The role of human saliva in aerosol-based transmission of SARS-CoV-2 has highlighted the need to understand the potential of oral hygiene products to inactivate the virus. Here we examined the efficacy of mouthwashes containing cetylpyridinium chloride (CPC) or chlorhexidine (CHX) in inactivating SARS-CoV-2. After 30 seconds contact under standard aqueous conditions CPC mouthwashes achieved a ≥4.0log10 PFU/mLreduction in SARS-CoV-2 (USA-WA1/2020) titres whereas comparable products containing CHX achieved <2.0log10 PFU/mL reduction. Further testing with CPC mouthwashes demonstrated efficacy against multiple SARS-CoV-2 variants, with inactivation below the limit of detection observed against the Alpha (B.1.1.7), Beta (B.1.35.1) and Gamma (P.1) variants. Virucidal efficacy of CPC mouthwash was also observed in the presence of human saliva with the product delivering ≥4.0log10 PFU/mL reduction in SARS-CoV-2 titres after 30 seconds providing additional evidence for the virucidal efficacy of CPC mouthwashes under simulated physiological conditions. Together these data suggest CPC-based mouthwashes are effective at inactivating SARS-CoV-2 and further supports the use of mouthwash to mitigate the risk of transmission during dentistry procedures.

The effect of mouthrinses on severe acute respiratory syndrome coronavirus 2 viral load

“…50 One preprint article reported that CHX (0.12%) achieved low, moderate, and high efficacy, depending on the viral strain used. 37 Meister and colleagues 46 reported low efficacy results after a 30-second rinse with a CHX mouthrinse with unknown concentration. Cetylpyridinium chloride (CPC) in vivo virucidal activity was studied in an RCT by Seneviratne and colleagues 22 on a group of 4 hospitalized patients (eTable 4, available online at the end of this article).…”

“…Studies included in qualitative synthesis n = 39 Regarding SARS-CoV-2 strains used across in vitro studies, several used well-characterized strains, the most used being USA-WA1/2020. [30][31][32][33][34][35][36][37][38] Four studies used a SARS-CoV-2 strain directly obtained from an infected patient, 39-42 whereas 1 study did not report the strain used. 43 In vitro studies were performed under dirty, [44][45][46][47][48] clean, 30,[32][33][34][35][36][38][39][40]42,43,[49][50][51][52][53][54][55] or both conditions, 37,41,56,57 with the terms dirty and clean referring to the existence of interfering substances.…”

“…[30][31][32][33][34][35][36][37][38] Four studies used a SARS-CoV-2 strain directly obtained from an infected patient, 39-42 whereas 1 study did not report the strain used. 43 In vitro studies were performed under dirty, [44][45][46][47][48] clean, 30,[32][33][34][35][36][38][39][40]42,43,[49][50][51][52][53][54][55] or both conditions, 37,41,56,57 with the terms dirty and clean referring to the existence of interfering substances. Two in vitro studies did not provide information about the existence of interfering substances.…”

Disinfection and decontamination in the context of SARS‐CoV‐2‐specific data

“…Formulations including hydrogen peroxide, benzalkonium chloride, dequalinium chloride, chlorhexidine, cetylpyridinium chloride, octenidine dihydrochloride, povidone–iodine, alkaline solutions, ethanol, hexetidine, cyclodextrin, polyaminopropyl biguanide, bioflavonoids, hypochlorous acid, delmopinol, silver nanoparticles, combination surfactants, essential oils, hydroxyapatite, glycyrrhizic acid, and/or sodium fluoride have been assessed. 150 , 154 , 169 , 172 , 174 , 175 , 176 , 177 , 178 , 179 , 180 , 181 , 182 , 183 , 184 , 185 , 186 Efficacy during in vitro or in vivo experiments has yielded variable results. Komine et al 175 did not find efficacy for chlorhexidine.…”

“…Others found reduced efficacy for hydrogen peroxide and chlorhexidine. 150 , 177 , 179 , 180 Cetylpyridinium chloride in various dilutions inactivates virus, and the mechanism of action in part appears to be related to the interruption of the Spike protein/receptor complex. 150 , 169 , 186 The degree of product dilution has a considerable impact.…”