key: cord-0732825-4ahmgq9j
authors: Elmahgoub, Fatima; Coll, Yasmine
title: Could certain mouthwashes reduce transmissibility of COVID-19?
date: 2021-06-25
journal: Evid Based Dent
DOI: 10.1038/s41432-021-0172-4
sha: 9e9ca04b3e7b8676cbe1bfb9084b33c02ed1561f
doc_id: 732825
cord_uid: 4ahmgq9j

Data sources Six electronic databases were searched including PubMed/Medline, Embase, Web of Science, Scopus, Cochrane, and Latin American and Caribbean Literature in Health Science (LILACS). Grey literature was also examined. There were no restrictions with regards to language, time of publication or participant demographics including gender, age and ethnicity. Study selection Both clinical and in vitro studies were included in the data search. Inclusion and exclusion criteria were clearly identified. Study selection was carried out in two phases by two independent reviewers. The studies included fitted the following criteria: studies that hypothesised the use of mouthwashes as a form of intervention to decrease the viral load in saliva contaminated with coronavirus. Two other studies were included in this review and both were conducted in Germany, performed in vitro, which tested povidone-iodine (PVP-I) mouthwash at two different concentrations: 1% and 7%. Both studies used the same culture mediums for clean and dirty conditions, and the evaluated outcome was the viral titre of MERS-CoV and SARS-CoV. The studies were published in 2015 and 2018. Neither study evaluated the action of this mouthwash on SARS-CoV-2 infection. Data extraction and synthesis The extraction of data followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline process. Studies chosen for analysis included assessment of the following data parameters for risk of bias: cell origin and cell type used, duration of exposure, frequency of exposure, magnetic flux density of exposure, environmental background magnetic field, use of control treatment, temperature control, blinding of exposure, randomisation of exposure, measurement of cell vitality, identical methods for control and exposure groups, randomisation of data measurements and potential industry sponsorship. Results One study assessed the effect of the mouthwash on MERS-CoV and the other on both MERS-CoV and SARS-CoV. In both studies, following 15 seconds of exposure to the mouthwash, a reduction in viral load of >99.99% was seen. There was a measurable reduction in viral titre in the samples, with one study reporting a reduction to 4.30 log10 TCID50/ml from 6.00-6.50 log10 TCID50/ml. Other mouthwashes such as hydrogen peroxide and chlorhexidine were not assessed in these studies. Conclusions The study concludes that PVP-I mouthwash at concentrations of 1% and 7% for 15 seconds may be effective at reducing the viral load of COVID-19 in human saliva. The level of scientific evidence, however, is low.

in viral titre in the samples, with one study reporting a reduction to 4.30 log10 TCID50/ml from 6.00-6.50 log10 TCID50/ml. Other mouthwashes such as hydrogen peroxide and chlorhexidine were not assessed in these studies.

The study concludes that PVP-I mouthwash at concentrations of 1% and 7% for 15 seconds may be effective at reducing the viral load of COVID-19 in human saliva. The level of scientific evidence, however, is low. Various studies have attempted to assess the potential effects of several mouthwashes on COVID-19 transmissibility. 2, 3, 4 This review aimed to identify whether there was evidence regarding a reduction in the viral load found in saliva following the use of three types of mouthwashes: chlorhexidine, hydrogen peroxide and povidone-iodine (PVP-I). Such evidence may be useful both in a clinical dental setting as well as confined public spaces, to reduce the risk of person-to-person transmissibility.

The literature search was found to be acceptable as six databases were explored, as well as grey literature, and there was no restriction on the language of studies included. In this review, the authors have followed the PRISMA guidelines and have registered the protocol with PROSPERO. The database search strategies were included within the article and the population, intervention, comparison and outcomes were clearly identified. A manual search of the literature was carried out to detect articles which addressed forms of prevention in dentistry in relation to COVID-19 and expert opinion was also sought in this search for relevant studies.

Studies with incomplete data were excluded.

This review was predominantly based on in vitro studies. Study selection was carried out in two phases: in the first phase, titles and abstracts were reviewed and 1,222 articles were identified and retrieved; duplicate articles were then removed. In the second phase, studies that met the eligibility criteria were chosen for full-text analysis. In total, ten articles were selected for complete reading. The reviewers were shielded with a third member acting as a moderator, to reduce bias. Where there was disagreement, a 

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