Use of an antiviral mouthwash as a barrier measure in the SARS-CoV-2 transmission in adults with asymptomatic to mild COVID-19: a multicentre, randomized, double-blind controlled trial

Objectives: To determine if commercially available mouthwash with beta-cyclodextrin and citrox (bioflavonoids) (CDCM) could decrease the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) salivary viral load. Methods: In this randomized controlled trial, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) PCR-positive patients aged 18-85 years with asymptomatic to mild coronavirus disease 2019 (COVID-19) symptoms for <8 days were recruited. A total of 176 eligible patients were randomly assigned (1:1) to CDCM or placebo. Three rinses daily were performed for 7 days. Saliva sampling was performed on day 1 at 09.00 (T1), 13.00 (T2) and 18.00 (T3). On the following 6 days, one sample was taken at 15.00. Quantitative RT-PCR was used to detect SARS-CoV-2. Results: The intention-to-treat analysis demonstrated that, over the course of 1 day, CDCM was significantly more effective than placebo 4 hours after the first dose (p 0.036), with a median percentage (log(10) copies/mL) decrease T1-T2 of-12.58% (IQR-29.55% to-0.16%). The second dose maintained the low median value for the CDCM (3.08 log(10) copies/mL; IQR 0-4.19), compared with placebo (3.31 log(10) copies/mL; IQR 1.18-4.75). At day 7, there was still a greater median percentage (log(10) copies/mL) decrease in salivary viral load over time in the CDCM group (-58.62%; IQR-100% to-34.36%) compared with the placebo group (-50.62%; IQR-100% to-27.66%). These results were confirmed by the per-protocol analysis. Conclusions: This trial supports the relevance of using CDCM on day 1 (4 hours after the initial dose) to reduce the SARS-CoV-2 viral load in saliva. For long-term effect (7 days), CDMC appears to provide a modest benefit compared with placebo in reducing viral load in saliva. (C) 2021 The Author(s). Published by Elsevier Ltd on behalf of European Society of Clinical Microbiology and Infectious Diseases.

Automated summary

The commercially available mouthwash with beta-cyclodextrin and citrox can effectively reduce the salivary viral load of SARS-CoV-2, showing significant short-term and long-term benefits over the placebo group on day 1 and day 7 respectively.