key: cord-0780136-xb4x2zjx authors: Gandhi, Gargi; Thimmappa, Latha; Upadhya, Nagaraja; Carnelio, Sunitha title: Could mouth rinses be an adjuvant in the treatment of SARS‐CoV‐2 patients? An appraisal with a systematic review date: 2021-10-29 journal: Int J Dent Hyg DOI: 10.1111/idh.12555 sha: b568bd64c8e04c826eac3849b384e7511c0803cf doc_id: 780136 cord_uid: xb4x2zjx 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. increase in viral load in the oral cavity. 5, 7, 8 Keeping in view this concept, it seems logical to curb this virus at the entry point itself. This review mainly focuses on chief antimicrobial ingredients of various nasal and oral rinses that could reduce the viral load in the oral cavity, oro-and nasopharynx. We aim to summarize the information related to antiviral agents acting against SARS-CoV-2 till date and potential ingredients present in oral rinses which could be effective in patients. SARS-CoV-2 virus belongs to the family of enveloped RNA viruses, coronaviridae. The presence of 'spike protein' (S protein) on its membrane envelope plays a significant role in the pathogenesis of this disease ( Figure 1 ). This S protein interacts mainly with the ACE2 receptors whose distribution in different parts of oral cavity indicates several virus entry points like non-keratinized mucosa of the mouth, epithelial cells of tongue and salivary glands. 5 Priming of the virus S protein is carried out with the help of the cellular transmembrane serine protease 2 (TMPRSS2). 5 Interestingly, individuals with healthy or poor oral hygiene status have reported viral load of SARS-CoV-2 in their saliva. 9, 10 This indicates that the oral tissues are a probable reservoir from which the SARS-CoV-2 virus can be transmissible during breathing, coughing, sneezing and talking. Although patients infected with this virus do not require hospitalization very often, the ones with comorbidities are prone to complications such as pneumonia, respiratory failure and multiple organ collapse. 11 Little is known about how transmission occurs from the oral cavity to the rest of the body causing systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS) in severe and fatal cases. 5 One of the theories can be that it invades through a periodontal pocket, then into the tissues and, finally into the blood stream as it is said that periodontitis seems to worsen the symptoms of COVID-19. 9 Another theory could be the settling of the virus on the tonsillar crypts and the oropharynx further going into the gastrointestinal tract and cause symptoms like diarrhoea. Cerebral involvement, considered a deadly form of this disease, is believed to be caused by the cellular receptor neuropilin-1 which binds with furin cleaved substrates forming a path of progression through central nervous system. 12, 13 Hence, a good understanding of its pathogenesis, site of entry, identifying and treating the disease at its earliest course can be useful for saving the humankind from this pandemic (Figures 2 and 3) . One of the striking symptoms which most of the people suffer when infected with COVID-19 is loss of smell seen even in severe allergic rhinitis or after an attack of cold. 12, 14 This could occur as the virus invades and binds to ACE2 receptors which support the nerve cells that detect smell and thereby their inflammation can cause anosmia. Although it is not known as to why there is a loss in taste, it is said that this is the consequence of loss of smell. 14 Another reason that could be the cause of ageusia is the alterations in protein and substance composition of the saliva. There are many substances in saliva that have affinity to bind with different foods of different taste and it is said that when COVID-19 invades the cells of salivary glands, it can cause alteration either in the composition or in the amount of saliva produced. 15, 16 Oral rinses or mouthwashes are frequently used for rinsing the teeth, gums, mouth and halitosis, before and after oral surgery/dental procedures because they contain antiseptic agents which help in killing the harmful oral microbes and reduce the microbial load in the aerosols generated during dental procedures. [17] [18] [19] Although there is a lack of evidence if mouthwashes act as effective antiviral agents that will reduce the SARS-CoV-2 transmission, the American Dental Association (ADA) has recommended the usage of preprocedural mouth wash povidone iodine (PVP-I; 0.2%) before any oral procedures for the safety of healthcare professionals and patients. 17 Due to the surge in COVID-19 cases and its high transmissible rates, researchers have carried in vitro studies to test the virucidal activity of common over-the-counter oral and nasal rinses as well as tailored formulae and have yielded promising results and this has paved the way for in vivo studies. There is a growing need for more clinical trials to test the safety and effectiveness of oral and nasal rinses and a study of long-term adverse effects too, if any. Although mouthwashes contain many ingredients such as antimicrobials, antivirals, flavouring agents, excipients, anti-halitosis agents, etc., we aim to focus on antiviral properties, since most of these mouthwashes are known to have antimicrobial properties. The World Health Organization (WHO) has not specified on the use of mouth rinses as a preventive or viral eradication measure in controlling COVID-19 but they have been used in controlling similar type of viral diseases. The present review followed the preferred reporting items for systematic reviews and meta-analysis (PRISMA) statement guidelines. 20 The objective of the review was to find the efficacy of oral rinses on virucidal property against n-coronavirus (in vivo studies). Clinical or in vivo studies that used mouthwashes, a form of intervention as a hypothesis for decreasing the viral load in saliva, were included. 1. Studies that evaluated mouthwashes for viruses other than SARS-CoV-2 infected individuals/saliva 2. Studies where the evaluation was carried with ingredients (antiseptic ingredients present in mouthwashes) other than saliva 3. Descriptive studies such as reviews, conference abstracts, expert opinions, chapter in books and case reports. The risk of bias (RoB) of individual studies was independently assessed by two authors (NU & SC) using the check list presented in Appendix S1. Quality criteria were designated with a positive sign (+) if an informative description was present, a negative sign (-) and if the informative description did not meet the criteria and a question mark (?) if the information was missing or insufficient. A study was classified to be 'low risk F I G U R E 2 Pathogenesis of COVID-19 disease CoV-2 in oral cavity of bias' with all positive scores, assigned to criteria of random allocation, defined inclusion/exclusion criteria, blinding to product and examiner, identical treatment between groups and reporting of follow-up. When two or more of these criteria were missing, the study was considered to have a high potential risk of bias. 21 The data were extracted using a data extraction sheet which included name of the first author, title, year of publication, country, study design, age and gender, sample size, type of intervention and control, time of testing the viral load, method of testing, bio-efficacy rate, statistical test used and limitation. The total number of articles from various databases were as fol- (Table 2 , online Appendix S1 and S2), although PVP-I was found to be efficient, the percentage and the time interval taken to test the efficacy against this virus was not consistent (methodological heterogeneity). [22] [23] [24] Chlorhexidine (CHX) as a combination of mouth rinse and oropharyngeal spray was found to be more effective than mouth rinse alone; cetylpyridinium chloride (CPC) did show promising results ( Table 2 ). The summary on the potential RoB estimated on various studies, as presented in the online Appendix S1, estimates high RoB in all study. [23] [24] [25] [26] [27] [28] A study related to oral rinse PVP-I reported thyroid dysfunction in 42% of their patients, the symptoms resolved following treatment discontinuation. 26 Hydrogen peroxide (H 2 O 2 ): is a widely used antimicrobial agent and studies have been conducted to demonstrate its effect on several viruses including SARS-CoV-2 and influenza. The oral microbiota produce H 2 O 2 physiologically and maintain a balance of oral microenvironment and it act on the epithelial cells that contain an enzyme, superoxide dismutase which catalyses the reaction converting H 2 O 2 into ion superoxide. This oxidative stress activates NF-ĸβ, leading to a local innate response that plays a major role in regulating host immune system and acting against viral infections. 8 So, it was proposed that washing nose, mouth and throat with H 2 O 2 may improve local innate responses to SARS-CoV-2 virus and increase protection against COVID-19 disease. In vitro studies have been done to test the action of H 2 O 2 against SARS-CoV-2 virus or just its S protein. [22] [23] [24] [25] [26] 29 A corona surrogate, transmissible gastroenteritis virus (TGEV), was dried on stainless steel to H 2 O 2 vapour (20 µl) for 2-3 h and was seen that about 5log10 reduction in viral load. This study proved H 2 O 2 to have good surface decontamination ability, but concerns were on relative susceptibility of viruses in vivo and safety dosage when used as oral/nasal rinse. 30 On the contrary, an in vivo study on 12 COVID-19 patients instructed to gargle mouth and throat with 20 ml of 1% H 2 O 2 for 30 s with a repeat RTPCR test after 30 min concluded no significant reduction in oral viral load and its use was questionable. 22, 23 More in vivo studies would give a clear scientific background of the use of this rinse. is composed of water-soluble polymer and polyvinyl pyrrolidone that acts as an antimicrobial agent which dissociates to release iodine, disrupting the membrane protein of microbes and is used as an antiseptic for skin disinfection before and after surgery. 8 Usually used topically, with the outbreak of COVID-19, its usage both nasally and orally was suggested by many frontline workers and researchers. 31, 32 Pelletier et al. 31 Cetylpyridinium chloride (CPC): is a quaternary ammonium compound having a broad antimicrobial activity, primarily on gram-positive bacteria. It has a lysosomotropic action and is able to destroy viral capsids. 48 It also shows a fungicidal effect on yeasts. As CPC is an antimicrobial, antiviral and antifungal agent, it was thought that it might have an action against enveloped viruses too, such as coronavirus. 8 This compound has been regarded as safe by Food Drug Administration and has the ability to act against SARS-CoV-2 virus. 49 A RCT concluded that salivary viral load decreased significantly with PVP-I and CPC mouth rinses at 6 h and a similar type of study has proved its efficacy against the virus. 27,50 Even a long-term use of CPC (around 6 weeks) does not disrupt the equilibrium of oral microbiota. 35, 50 A combination of CPC (0.075%) and zinc lactate (0.28%) proves its efficacy in saliva up to 60 min after rinsing. 46 Since just a handful of studies are available with respect to (w.r.t) CPC and its action against coronavirus, this is an area of research that has a lot of potential to be explored. Longterm use of these mouth washes needs to be monitored. Ethanol is a common excipient used in several oral rinses and has been observed as an effective agent against SARS-CoV-2 virus. It acts by attacking the lipid membrane of the micro-organisms, denatures proteins and lipid structure. It primarily inactivates enveloped virus at a higher concentration than what is deemed safe for oral use and is added in lower concentrations in many mouthwashes (14-27% weight/volume). 27,51,52 Bidra et al. 26 reported that use of 70% of ethanol for 30 s inactivated SARS-CoV-2 virus. Studies are required to standardize the use of non-toxic concentrations of ethanol which will inactivate SARS-CoV-2 virus. Therefore, in vitro and in vivo studies should be carried out in order to define its role against SARS-CoV-2 prior to its use in oral and nasal rinses. Combinations of antimicrobial and antiviral agents: are also being tested so as to have a more effective bactericidal and virucidal activity owing to a cumulative effect of such combinations. Most of the mouthwashes are alcohol based owing to increased antibacterial and antiviral activity. Precautions need to be taken with usage of alcohol-based rinses in vulnerable groups (children, pregnant women and people with previous alcohol addiction). CHX 0.06%, sodium fluoride (NaF, 0.025%) and CPC 0.03% proved to be effective as non-alcohol-based oral rinses. 52 We believe that such combinations should be used and their activity should even be tested against SARS-CoV-2 virus too. A study by de Fonseca et al. 53 indicated that a phthalocyanine derivate-based mouthwash shows promising action in reducing SARS-CoV-2 viral load. Five millilitre of phthalocyanine derivate mouthwash for 1 min, five times daily for 2 weeks, reduced the clinical symptoms of the disease. The limitations of this study is a small sample size, lack of control group and the fact that lack of RTPCR test on patients' salivary samples before and after use of the mouth TA B L E 1 Evidence-based non-randomized in vivo studies on efficacy of oral rinses against SARS-CoV-2 Citrox, a derivative of citrus fruits, a soluble bioflavonoid and inhibitor of the 3-chymotrypsin-like protease of the SARS-CoV-2 is a protein vital to virus replication or inhibits binding to ACE2 receptors. 61 It has the property of oxidizing the virus, and thus reduces its salivary load. Similarly, β-cyclodextrin (β-CD), a modified sugar molecule, has the property of targeting its lipid bilayer by sequestering cholesterol and attracts viruses before inactivating it irreversibly. 61, 62 Thus, a combination of these agents (Cyclodextrins combined with Citrox) were used as mouth rinses and/or nasal rinse in a RCT that found a remarkable decrease in the salivary viral load on day 1, 4 h after the initial dose and a modest decrease in the viral load was observed as a long-term effect (7 days). 62 Salt water gargle, as well as nasal irrigation, is said to decrease the viral load. 28 As the COVID-19 second-wave reaches its peak, it has gotten all the more very importance that we ramp up our clinical testing, in vitro and in vivo studies, as we seem to have quite a few positive outcomes in various studies mentioned in this review. Some agents such as EOs and phthalocyanine derivates seem to aid in reducing the clinical se- The RCTs of oral rinse/mouthwashes on SARCoV-2 give an evidencebased approach on the use of the antiseptic (PVP-I of 0.5%-1%) having virucidal properties, as a preprocedural rinse such that it will decrease the viral load in both asymptomatic and symptomatic patients, and also in preventing cross-infections between patients and treating dental or medical personnel. As per the occupational safety and health administration guidelines, this mouth rinse is safe and cost-effective, and could also be used as a prophylactic measure in venerable population. None. There are no conflicts of interest. Gargi Gandhi, first author, contributed to the acquisition, analysis and interpretation of data, and drafted the manuscript. Latha Thimmappa contributed to the design of study, the acquisition, analysis and interpretation of data, and drafted the manuscript. Nagaraja Upadhya contributed to the design of study and critically revised the manuscript. Sunitha Carnelio contributed to the conception and design of the study, supported the analysis and interpretation of the data and critically revised the manuscript. All authors gave final approval and agreed to be accountable for all aspects of this work, ensuring its integrity and accuracy. Ethical committee clearance is not required as this is a systematic review based on the published articles. The data that support the findings of this study are openly available in [repository name] at [DOI] . Gargi Gandhi https://orcid.org/0000-0003-3777-1493 Sunitha Carnelio https://orcid.org/0000-0002-2789-3692 Inactivation of SARS-CoV-2 through treatment with the mouth rinsing solutions ViruProX ® and BacterX ® Pro Triple mutation Covid variant in India? 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