Salivary SARS-CoV-2 load reduction with mouthwash use: A randomized pilot clinical trial

Utilizing the Potential of Antimicrobial Peptide LL-37 for Combating SARS-COV- 2 Viral Load in Saliva: an In Silico Analysis

Limiting the spread of virus during the recent pandemic outbreak was a major challenge. Viral loads in saliva, nasopharyngeal and oropharyngeal swabs were the major cause for droplet transmission and aerosols. Saliva being the major contributor for the presence of viral load is the major key factor; various mouthwashes and their combination were analyzed and utilized in health care centers to hamper the spread of virus and decrease viral load. The compositions of these mouthwashes to an extent affected the viral load and thereby transmission, but there is always a scope for other protocols which may provide better results. Here we evaluated the potential of antimicrobial peptide LL-37 in decreasing the viral load of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) through an in silico work and evidence from other studies. This narrative review highlighted a brief nonsystematic methodology to include the selected articles for discussion. Accessible electronic databases (Medline, Scopus, Web of Science, SciELO, and PubMed) were used to find studies that reported the salivary viral load of SARS-CoV-2 published between December 2019 and June 2021. The following keywords were utilized for brief searching of the databases: "saliva," "viral load," and "SARS-CoV-2." Articles in English language, in vitro cell-line studies, ex vivo studies, and clinical trials explaining the viral load of SARS-CoV-2 in saliva and strategies to decrease viral load were included in this review. The search was complemented by manual searching of the reference lists of included articles and performing a citation search for any additional reviews. The antiviral potential of cationic host defense peptide LL-37 was evaluated using computational approaches providing in silico evidence. The analysis of docking studies and the display of positive interfacial hydrophobicity of LL-37 resulting in disruption of COVID-19 viral membrane elucidate the fact that LL-37 could be effective against all variants of SARS-CoV-2. Further experimental studies would be needed to confirm the binding of the receptor-binding domain with LL-37. The possibility of using it in many forms further to decrease the viral load by disrupting the viral membrane is seen.

The effect of mouthwashes on SARS-CoV-2 viral load: a systematic review

Background

Considering that the oral cavity is a major entryway and reservoir for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the aim of the authors was to perform a systematic review of in vivo and in vitro studies to assess the effectiveness of mouthrinses on SARS-CoV-2 viral load.

Types of Studies Reviewed

The authors searched PubMed, Web of Science, Scopus, MedRxiv, and bioRxiv databases, including in vitro and in vivo studies assessing the virucidal effect of mouthrinses on SARS-CoV-2 or surrogates. From a total of 1,622 articles retrieved, the authors included 39 in this systematic review.

Results

Povidone-iodine was the most studied mouthrinse (14 in vitro and 9 in vivo studies), frequently showing significant reductions in viral load in in vitro assays. Similarly, cetylpyridinium chloride also showed good results, although it was evaluated in fewer studies. Chlorhexidine gluconate and hydrogen peroxide showed conflicting results on SARS-CoV-2 load reduction in both in vitro and in vivo studies.

Practical Implications

Povidone-iodine–based mouthrinses appear to be the best option as an oral prerinse in the dental context for SARS-CoV-2 viral load reduction. Although the results of primary studies are relevant, there is a need for more in vivo studies on mouthrinses, in particular, randomized controlled clinical trials, to better understand their effect on SARS-CoV-2 viral load and infection prevention.

Effect of Pudilan Keyanning antibacterial mouthwash on dental plaque and gingival inflammation in patients during periodontal maintenance phase: study protocol for double-blind, randomised clinical trial

INTRODUCTION

Plaque control plays a critical role in the prevention and treatment of periodontitis. Antibacterial mouthwash is one of the most important tools for plaque control. Pudilan, including extracts of Scutellaria baicalensis root, Taraxacum mongolicum, Bunge corydalis herb and Isatis indigotica, was reported playing the role of anti-inflammatory and anti-bacterial. However, its effect on dental plaque and periodontal inflammation remains unknown. We aimed to assess the efficacy of Pudilan Keyanning antibacterial mouthwash which contains the active essence of Pudilan and 0.03%-0.06% cetylpyridinium chloride, as well as Pudilan active essence for plaque control and gingival anti-inflammation in patients during periodontal maintenance phase.

METHODS AND ANALYSIS

In this double-blind, randomised, placebo-controlled clinical trial, a total of 120 participants during periodontal maintenance phase will be enrolled. After supragingival scaling, they will be randomly assigned into three groups in a 1:1:1 ratio: the Pudilan Keyanning antibacterial mouthwash group, a chlorhexidine acetate mouthwash (0.12%) group or a placebo group with mouthwash containing the same components as the Pudilan Keyanning mouthwash except for Pudilan active ingredients. They will rinse with mouthwash, respectively, two times per day for 6 weeks. Clinical parameters (such as plaque index, bleeding index) and the level of volatile sulfide in the breath will be measured and analysed. The subgingival plaque will be collected and analysed microbiologically. Questionnaire feedback will be analysed.

ETHICS AND DISSEMINATION

The study protocol (V.4) was reviewed and approved by the Medical Ethical Committee of Peking University School and Hospital of Stomatology (Ethics Approval No. PKUSSIRB-201950153b). All participants signed a written consent form.

TRIAL REGISTRATION NUMBER

ChiCTR2000041253.

In vitro comparison of the tensile strength of elastomeric ligatures exposed to Povidone Iodine 1%, Chlorhexidine 0.02%, and hydrogen peroxide 5

OBJECTIVE

In orthodontic patients using any chemical substances in oral environment could change the elastomeric properties of their appliances. Since the beginning of the SARS-CoV-2 pandemic, efforts have been devoted to explore methods of prevention including the use of antiviral mouthwashes. This study aimed to investigate the effects of Povidone Iodine (PVP-I) and two other disinfecting solutions on the mechanical properties of orthodontic elastomeric ligatures.

MATERIALS AND METHODS

In this study, 130 elastomeric ligatures in five groups (three test groups and two control groups) were examined in laboratory conditions for a period of 28 days. In the control group, specimens were kept dry in a dark environment while all other ligatures were stored in artificial saliva. Elastomeric ligatures were immersed into PVP-I solution (1%) Chlorhexidine (0.02%), and hydrogen peroxide (5%) for one minute each day in three time intervals of one day, 7 days and 28 days. Next, the maximum tensile strength of elastomeric ligatures was tested by a universal testing machine (CN 1174, Germany).

RESULTS

The results showed that the tensile strength of elastomeric ligatures was significantly decreased in all three test groups after 28 days (p-value<0.05). However, the difference between groups was not statistically significant. Between-subject ANOVA test showed that there were significant correlations between the time of exposure and type of disinfecting solutions.

CONCLUSIONS

PVP-I has comparable effects on elastomeric ligatures as artificial saliva, chlorhexidine, and hydrogen peroxide.

Concordance between PCR-based extraction-free saliva and nasopharyngeal swabs for SARS-CoV-2 testing

Introduction: Saliva represents a less invasive alternative to nasopharyngeal swab (NPS) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection. SalivaDirect is a nucleic acid extraction-free method for detecting SARS-CoV2 in saliva specimens. Studies evaluating the concordance of gold standard NPS and newly developed SalivaDirect protocols are limited. The aim of our study was to assess SalivaDirect as an alternative method for COVID-19 testing. Methods: Matching NPS and saliva samples were analysed from a cohort of symptomatic (n=127) and asymptomatic (n=181) participants recruited from hospital and university settings, respectively. RNA was extracted from NPS while saliva samples were subjected to the SalivaDirect protocol before RT-qPCR analysis. The presence of SARS-Cov-2 was assessed using RdRp and N1 gene targets in NPS and saliva, respectively. Results: Overall we observed 94.3% sensitivity (95% CI 87.2-97.5%), and 95.9% specificity (95% CI 92.4-97.8%) in saliva when compared to matching NPS samples. Analysis of concordance demonstrated 95.5% accuracy overall for the saliva test relative to NPS, and a very high level of agreement (κ coefficient = 0.889, 95% CI 0.833-0.946) between the two sets of specimens. Fourteen of 308 samples were discordant, all from symptomatic patients. Ct values were >30 in 13/14 and >35 in 6/14 samples. No significant difference was found in the Ct values of matching NPS and saliva sample ( p=0.860). A highly significant correlation (r = 0.475, p<0.0001) was also found between the Ct values of the concordant positive saliva and NPS specimens. Conclusions: Use of saliva processed according to the SalivaDirect protocol represents a valid method to detect SARS-CoV-2. Accurate and less invasive saliva screening is an attractive alternative to current testing methods based on NPS and would afford greater capacity to test asymptomatic populations especially in the context of frequent testing.

Virucidal efficacy of chlorhexidine: a systematic review

This study aimed to systematically review the literature about the virucidal efficacy of CHX in comparison to other substances used in the oral cavity. Electronic searches were performed in four databases (PubMed, Scopus, Embase, and Web of Science). Only studies that presented the following characteristics were included: (1) verified virucidal efficacy of CHX against Herpes Simplex Type-1 (HSV-1), any Influenza, or any human coronavirus (HcoV); and (2) compared the virucidal efficacy of CHX with essential oils (Listerine^®), quaternary ammonium compounds, povidone-iodine, hydrogen peroxide, negative control substance, and absence of therapy. Two researchers independently selected the studies, extracted data and evaluated the risk of bias. A narrative data synthesis was used. Twenty-five studies were included, of which 21 were in vitro and four were randomized clinical trials (RCT). Studies assessed the virucidal efficacy of CHX against Herpes Simplex Type-1 (HSV-1) (10 studies), Influenza A (InfluA) (4 studies), human coronavirus (HCoV) (4 studies) and Severe Acute Respiratory Syndrome-Related Coronavirus (SARS-CoV-2) (11 studies). Most studies demonstrated that CHX has a positive virucidal efficacy against HSV-1 and InfluA strains. However, lower efficacy was shown to InfluA strain in comparison to povidone-iodine. Lower to none virucidal efficacy of CHX is expected for HCoV and SARS-CoV-2 strains for in vitro studies. Three RCT demonstrated that CHX was able to significantly reduce the viral load of SARS-CoV-2 for a short period. CHX may present an interesting virucidal efficacy against HSV-1 and InfluA viruses. CHX also presents transient efficacy against SARS-CoV-2 when used as a mouthwash.

Could mouth rinses be an adjuvant in the treatment of SARS-CoV-2 patients? An appraisal with a systematic review

Objective

A wide variety of mouth rinses are available to combat micro‐organisms in the oral cavity. At the present global pandemic, the need of the hour is to control the viral infection due to the novel corona virus SARS‐COV‐2, as its port of entry is through the receptors located in the oral and pharyngeal mucosa. This systematic literature review focuses on the in vivo studies [randomized control trials (RCTs)] done on the efficacy of existing mouth rinses which have been used in reducing the viral loads.

Methods

The electronic database which includes PubMed‐MEDLINE, Google scholar, Scopus, Web of Science, EMBASE, ProQuest and CINAHL was searched from December 2019 to June 2021 with appropriate Medical Subject Headings (MeSH) terms and Boolean operators. Two reviewers independently reviewed the abstracts.

Results

Of the 2438 retrieved titles, 905 remained after removing duplicates. Twelve articles were eligible to be included in this review of which seven were randomized with adequate sample size.

Conclusions

Mouth washes containing povidone iodine and chlorhexidine decrease the viral load transiently. Large amount of in vivo studies are of paramount importance, especially RCTs, to prove the efficacy of these mouth rinses.

The effectiveness of mouthwash against SARS-CoV-2 infection: A review of scientific and clinical evidence

BACKGROUND/PURPOSE

The COVID-19 pandemic, caused by the spread of SARS-CoV-2 infection that is mainly through the airborne transmission, is a worldwide health concern. This review seeks to assess the potential effectiveness of mouthwash in reducing the oropharyngeal load of SARS-CoV-2 based on the available evidence.

METHODS

Articles related to mouthwash and COVID-19 in PubMed were electronically searched in July, 2021. After manually excluding articles lacking sufficient scientific evidence or validation processes, those with inaccessible online full text, those that did not test the effectiveness of mouthwash against SARS-CoV-2, and those not written in English, 17 original and 13 review articles were chosen for this review.

RESULTS

The eligible articles revealed that the main virucidal mechanism of mouthwash was via interactions with the viral envelope. Povidone-iodine (PVP-I), cetylpyridinium chloride (CPC), and essential oils with ethanol showed virucidal effects on SARS-CoV-2 in vitro, potentially by interfering with the viral envelope. A few clinical studies demonstrated that PVP-I, CPC, hydrogen peroxide, and chlorhexidine reduced the oropharyngeal load of SARS-CoV-2.

CONCLUSION

Although the available evidence is limited, mouthwash containing PVP-I or CPC shows potential for reducing the oropharyngeal load of SARS-CoV-2 and thus may present a risk-mitigation strategy for COVID-19 patients.

Concordance between PCR-based extraction-free saliva and nasopharyngeal swabs for SARS-CoV-2 testing

Introduction: Saliva represents a less invasive alternative to nasopharyngeal swab (NPS) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection. SalivaDirect is a nucleic acid extraction-free method for detecting SARS-CoV2 in saliva specimens. Studies evaluating the concordance of gold standard NPS and newly developed SalivaDirect protocols are limited. The aim of our study was to to assess SalivaDirect as an alternative method for COVID-19 testing. Methods: Matching NPS and saliva samples were analysed from a cohort of symptomatic (n=127) and asymptomatic (n=181) participants recruited from hospital and university settings, respectively. RNA was extracted from NPS while saliva samples were subjected to the SalivaDirect protocol before RT-qPCR analysis. The presence of SARS-Cov-2 was assessed using RdRP and N1 gene targets in NPS and saliva, respectively. Results: Overall we observed 94.3% sensitivity (95% CI 87.2-97.5%), and 95.9% specificity (95% CI 92.4-97.8%) in saliva when compared to matching NPS samples. Analysis of concordance demonstrated 95.5% accuracy overall for the saliva test relative to NPS, and a very high level of agreement (κ coefficient = 0.889, 95% CI 0.833-0.946) between the two sets of specimens. Fourteen of 308 samples were discordant, all from symptomatic patients. Ct values were >30 in 13/14 and >35 in 6/14 samples. No significant difference was found in the Ct values of matching NPS and saliva sample ( p=0.860). A highly significant correlation (r = 0.475, p<0.0001) was also found between the Ct values of the concordant positive saliva and NPS specimens. Conclusions: Use of saliva processed according to the SalivaDirect protocol represents a valid method to detect SARS-CoV-2. Accurate and less invasive saliva screening is an attractive alternative to current testing methods based on NPS and would afford greater capacity to test asymptomatic populations especially in the context of frequent testing.