Saliva is a non-negligible factor in the spread of COVID-19

The effect of novel vitamin D3 compounds on saliva samples from COVID-19 patients: a lab study

Vitamin D has shown antimicrobial effects. This study aimed to explore the antiviral effects of vitamin D3 on saliva samples collected from patients with coronavirus disease-19 (COVID-19) and compare saliva and swab results to aid in policy development. Saliva and swab samples were collected from adult patients with a positive test for COVID-19 at the King Faisal Specialist Hospital and Research Centre, Jeddah. Patients who were immunocompromised and pregnant and aged < 18 years were excluded. Vitamin D3 compound (100, 300, 800, and 1,200 IU) was added to the first saliva sample in the laboratory (n = 20); the rest of the swab specimens were compared with the saliva samples via real-time polymerase chain reaction. Of the 257 patients, 236 (94.8%) had positive saliva sample test results, 7 (2.8%) had errors, and 6 (2.4%) had negative results. Of the 236 positive tests, 235 (99.6%) had a cycle threshold (Ct) indicating strong positive reactions, and only one (Ct = 28.86) was weak. Among the 236 positive results, 235 (99.6%) exhibited robust positive reactions, indicating a substantial positive sample size. Thus, saliva might be a dependable alternative testing tool when obtaining swab samples from patients is inconvenient or challenging.

ACE2 expression and spike S1 protein-mediated immune responses in oral mucosal cells

OBJECTIVES

ACE2, known as a host receptor involved with SARS-CoV-2 infection, binds to viral spike proteins for host cell entry. However, details regarding its induction and function in oral mucosal cells remain unknown.

MATERIALS AND METHODS

We examined ACE2 expression and its induction by transfected mimic nucleotides and pro-inflammatory cytokines in oral keratinocytes (RT7) and fibroblasts (GT1). Subsequently, the effects of viral spike S1 protein via ACE2 on CXCL10 expression induced by pro-inflammatory cytokines in both cells were examined.

RESULTS

ACE2 was constitutively expressed in RT7 and GT1. Transfected Poly(I:C) and Poly(dA:dT) increased ACE2 expression in those cells, while knockdown of RIG-I decreased ACE2 expression induced by those transfected ds nucleotides. IFN-γ and TNF-α enhanced transfected ds nucleotides-induced ACE2 expression in RT7 but not GT1. S1 protein alone did not affect CXCL10 expression in either cell type, whereas it enhanced IFN-β-induced CXCL10 in both, while immune responses of IFN-γ- and TNF-α-induced CXCL10 enhanced by S1 protein were different between RT7 and GT1. Finally, knockdown of ACE2 decreased cytokines and S1 protein mediated-CXCL10 levels in both cells.

CONCLUSIONS

ACE2 in oral mucosal cells may contribute to development of infection and inflammation in cooperation with pro-inflammatory cytokines following SARS-CoV-2 invasion.

Contribution of Particulates to Airborne Disease Transmission and Severity: A Review

The emergence of coronavirus disease 2019 (COVID-19) has catalyzed great interest in the spread of airborne pathogens. Airborne infectious diseases are classified into viral, bacterial, and fungal infections. Environmental factors can elevate their transmission and lethality. Air pollution has been reported as the leading environmental cause of disease and premature death worldwide. Notably, ambient particulates of various components and sizes are harmful pollutants. There are two prominent health effects of particles in the atmosphere: (1) particulate matter (PM) penetrates the respiratory tract and adversely affects health, such as heart and respiratory diseases; and (2) bioaerosols of particles act as a medium for the spread of pathogens in the air. Particulates contribute to the occurrence of infectious diseases by increasing vulnerability to infection through inhalation and spreading disease through interactions with airborne pathogens. Here, we focus on the synergistic effects of airborne particulates on infectious disease. We outline the concepts and characteristics of bioaerosols, from their generation to transformation and circulation on Earth. Considering that microorganisms coexist with other particulates as bioaerosols, we investigate studies examining respiratory infections associated with airborne PM. Furthermore, we discuss four factors (meteorological, biological, physical, and chemical) that may impact the influence of PM on the survival of contagious pathogens in the atmosphere. Our review highlights the significant role of particulates in supporting the transmission of infectious aerosols and emphasizes the need for further research in this area.

Rapid increase in salivary IgA and broad recognition of spike protein following SARS-CoV-2 vaccination

Saliva is a key component of mucosal immunity, which protects the oral cavity from viral infections. However, salivary immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in terms of immunoglobulin dynamics and recognition, have not been investigated sufficiently. In this study, saliva samples were collected from individuals that received SARS-CoV-2 vaccine, and immunoglobulin G (IgG), IgM, and IgA against whole spike protein and S1 protein were measured. IgA against whole spike protein increased significantly following vaccination, while IgA against S1 protein did not. Of note, the IgA response was evident two weeks after the first vaccine dose and continued to rise thereafter. On the contrary, IgG antibodies against S1 increased significantly at four weeks after vaccination. These results reveal the dynamics and recognition antigens of immunoglobulins in saliva, indicating the function of IgA in the mucosal immune system. These findings may pave the way for further studies on mucosal immune response induced by vaccination.

The Role of Socioeconomic and Health Services Organizational Factors on Infection Control Structure Score, Brazil

This study aimed to analyze possible associations between the Infection Control Structure Score (ICSS), health services, and social characteristics of the municipalities in Brazil. Secondary data from the third cycle 2017-2018 of the Brazilian National Program for Improving Primary Care Access and Quality (PMAQ) was analyzed. Six independent variables - FIRJAN Index of Municipal Development, number of inhabitants, number of family health teams receiving a financial incentive from the federal government, healthcare expenditure per capita, and number of Oral Health Teams modalities 1 and 2 - were included to assess their influence on ICSS, measured for each Brazilian town. Data analysis used the Classification and Regression Tree model performed with IBM SPSS 25. A total of 4,900 municipalities were included, and the mean ICSS was 0.905 (±0.092). A positive relationship was observed between healthcare expenditure per capita, municipal development, and the outcome. Conversely, towns with a higher number of family health teams receiving a financial incentive from the federal government showed lower mean ICSS. The findings suggest that inequalities in the infection control structures exist within the country, and they were related to the health services and social characteristics of the municipalities.

A pan-SARS-CoV-2-specific soluble angiotensin-converting enzyme 2-albumin fusion engineered for enhanced plasma half-life and needle-free mucosal delivery

Immunocompromised patients often fail to raise protective vaccine-induced immunity against the global emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants. Although monoclonal antibodies have been authorized for clinical use, most have lost their ability to potently neutralize the evolving Omicron subvariants. Thus, there is an urgent need for treatment strategies that can provide protection against these and emerging SARS-CoV-2 variants to prevent the development of severe coronavirus disease 2019. Here, we report on the design and characterization of a long-acting viral entry-blocking angiotensin-converting enzyme 2 (ACE2) dimeric fusion molecule. Specifically, a soluble truncated human dimeric ACE2 variant, engineered for improved binding to the receptor-binding domain of SARS-CoV-2, was fused with human albumin tailored for favorable engagement of the neonatal fragment crystallizable receptor (FcRn), which resulted in enhanced plasma half-life and allowed for needle-free transmucosal delivery upon nasal administration in human FcRn-expressing transgenic mice. Importantly, the dimeric ACE2-fused albumin demonstrated potent neutralization of SARS-CoV-2 immune escape variants.

Assessment of infection control in oral radiology during the COVID-19 outbreak: An international collaborative study

Purpose

In the context of COVID-19, studies evaluating the adherence of dentists and dental students to infection control are relevant due to their high occupational exposure and risk, as well as their responsibility for disseminating information and good practices. This study evaluated the adherence of dentists and dental students to infection control in the oral radiology field in the setting of the COVID-19 pandemic on different continents.

Materials and Methods

This cross-sectional observational study involved individuals who performed intraoral radiographic examinations during the COVID-19 pandemic. The Questionnaire on Infection Control in Oral Radiology was administered virtually using a Google Form. Participants from different continents (the Americas, Africa, Europe, Asia, and Oceania) were recruited. Data were subjected to descriptive analysis and simple and multiple binary regression (5%).

Results

There were 582 valid answers, and 68.73% of the participants were from the Americas, 18.90% from Europe, and 12.37% from Asia. The median score for infection control protocols was 94 points for dental students and 104 points for dentists, and participants below the median were considered to have low adherence to infection control in oral radiology. Low access to infection control was found for 53.0% of dentists in the Americas, 34.0% from Europe, and 26.9% from Asia.

Conclusion

The adherence to infection control protocols in oral radiology was low even in the face of the COVID-19 pandemic. The results may help improve the awareness of students and professionals, since oral radiology routines have the potential for transmitting COVID-19.

Effect of herbal mouthrinsein dental ultrasonic scalers among Indians

The use of herbal mouthrinse is gaining momentum in recent years. Therefore, it is of interest to evaluate the effect of 2 herbal mouthrinse (curcumin, cinnamon) in comparison with2 conventional mouthrinse (povidone iodine, chlorhexidine) when used as coolant in dental ultrasonic scalers. Hence, 200 participants were included in this study. Analysis of gingival index, periodontal index at baseline and one month follow up was completed. The inhibitory effects of both conventional and herbal mouth rinse in gingival health are similar. However, cinnamon and curcumin owing to its minimal adverse effects and low cost is useful as an alternative to chlorhexidine for reducing bacterial load in dental aerosols produced due to ultrasonic scalers.

Delivery of biologics: Topical administration

Biologics are unaffordable to a large majority of the global population because of prohibitively expensive fermentation systems, purification and the requirement for cold chain for storage and transportation. Limitations of current production and delivery systems of biologics were evident during the recent pandemic when <2.5% of vaccines produced were available to low-income countries and ∼19 million doses were discarded in Africa due to lack of cold-chain infrastructure. Among FDA-approved biologics since 2015, >90% are delivered using invasive methods. While oral or topical drugs are highly preferred by patients because of their affordability and convenience, only two oral drugs have been approved by FDA since 2015. A newly launched oral biologic costs only ∼3% of the average cost of injectable biologics because of the simplified regulatory approval process by elimination of prohibitively expensive fermentation, purification, cold storage/transportation. In addition, the cost of developing a new biologic injectable product (∼$2.5 billion) has been dramatically reduced through oral or topical delivery. Topical delivery has the unique advantage of targeted delivery of high concentration protein drugs, without getting diluted in circulating blood. However, only very few topical drugs have been approved by the FDA. Therefore, this review highlights recent advances in oral or topical delivery of proteins at early or advanced stages of human clinical trials using chewing gums, patches or sprays, or nucleic acid drugs directly, or in combination with, nanoparticles and offers future directions.

Effects of tea, catechins and catechin derivatives on Omicron subvariants of SARS-CoV-2

The Omicron subvariants of SARS-CoV-2 have multiple mutations in the S-proteins and show high transmissibility. We previously reported that tea catechin (-)-epigallocatechin gallate (EGCG) and its derivatives including theaflavin-3,3'-di-O-digallate (TFDG) strongly inactivated the conventional SARS-CoV-2 by binding to the receptor binding domain (RBD) of the S-protein. Here we show that Omicron subvariants were effectively inactivated by green tea, Matcha, and black tea. EGCG and TFDG strongly suppressed infectivity of BA.1 and XE subvariants, while effect on BA.2.75 was weaker. Neutralization assay showed that EGCG and TFDG inhibited interaction between BA.1 RBD and ACE2. In silico analyses suggested that N460K, G446S and F490S mutations in RBDs crucially influenced the binding of EGCG/TFDG to the RBDs. Healthy volunteers consumed a candy containing green tea or black tea, and saliva collected from them immediately after the candy consumption significantly decreased BA.1 virus infectivity in vitro. These results indicate specific amino acid substitutions in RBDs that crucially influence the binding of EGCG/TFDG to the RBDs and different susceptibility of each Omicron subvariant to EGCG/TFDG. The study may suggest molecular basis for potential usefulness of these compounds in suppression of mutant viruses that could emerge in the future and cause next pandemic.

Milk Casein Inhibits Effect of Black Tea Galloylated Theaflavins to Inactivate SARS-CoV-2 In Vitro

Continuing caution is required against the potential emergence of SARS-CoV-2 novel mutants that could pose the next global health and socioeconomical threats. If virus in saliva can be inactivated by a beverage, such a beverage may be useful because the saliva of infected persons is the major origin of droplets and aerosols that mediate human-to-human viral transmission. We previously reported that SARS-CoV-2 was significantly inactivated by treatment in vitro with tea including green tea and black tea. Catechins and its derived compounds galloylated theaflavins (gTFs) bound to the receptor-binding domain (RBD) of the S-protein and blocked interaction between RBD and ACE2. Black tea is often consumed with sugar, milk, lemon juice, etc., and it remains unclarified whether these ingredients may influence the anti-SARS-CoV-2 effect of black tea. Here, we examined the effect of black tea on Omicron subvariants in the presence of these ingredients. The infectivity of Omicron subvariants was decreased to 1/100 or lower after treatment with black tea for 10 s. One or two teaspoons of milk (4~8 mL) completely blocked the anti-viral effect of a cup of tea (125 mL), whereas an addition of sugar or lemon juice failed to do so. The suppressive effect was dose-dependently exerted by milk casein but not whey proteins. gTFs were coprecipitated with casein after acidification of milk-supplemented black tea, strongly suggesting the binding of gTFs to casein. The present study demonstrates for the first time that an addition of milk cancelled the anti-SARS-CoV-2 effect of black tea due to binding of casein to gTFs.

Evaluating the microbial aerosol generated by dental instruments: addressing new challenges for oral healthcare in the hospital infection

BACKGROUND

Using a rotary instrument or ultrasonic instrument for tooth preparation is a basic operation in the dental clinic that can produce a significant number of droplets and aerosols. The dental droplet and aerosol can lead to the transfer of harmful germs. The goal of this study was to analyze the properties of microbiological aerosol created by droplets and aerosol generated by three common tooth-preparation instruments.

METHODS

Streptococcus mutans UA159 was used as the biological tracer to visualize the droplets and aerosols. The passive sampling method was used to map the three-dimensional spatial distribution and the six-stage Andersen microbial sampler (AMS) was used as the active sampling method to catch aerosol particles at a specific time.

RESULTS

The aerosol concentration is related to instruments, three-dimensional spatial distribution, and dissipation time. Most aerosols were generated by air turbines. More microorganisms are concentrated at the 1.5 m plane. The majority of the post dental procedure contamination was detected within the 0-10-min period and it decreased rapidly within 30 min.

CONCLUSION

This study is conducive to the proposal and improvement of relevant infection control measures in dental procedures and provides a basis for the assessment of measures, reducing the risk of nosocomial infection.

SARS-CoV-2 antigen detection by saliva; an alternative to nasopharyngeal specimen: A cross-sectional study

Background and Aims

Saliva samples are less invasive and more convenient for patients than naso- and/or oropharynx swabs (NOS). However, there is no US Food and Drug Administration-approved severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapid antigen test kit, which can be useful in a prolonged pandemic to reduce transmission by allowing suspected individuals to self-sampling. We evaluated the performances of High sensitive AQ+ Rapid SARS-CoV-2 Antigen Test (AQ+ kit) using nasopharyngeal swabs (NPs) and saliva specimens from the same patients in laboratory conditions.

Methods

The real-time reverse transcription-polymerase chain reaction (rRT-PCR) test result was used for screening the inrolled individuals and compared as the gold standard. NP and saliva samples were collected from 100 rRT-PCR positives and 100 negative individuals and tested with an AQ+ kit.

Results

The AQ+ kit showed good performances in both NP and saliva samples with an overall accuracy of 98.5% and 94.0%, and sensitivity of 97.0% and 88.0%, respectively. In both cases, specificity was 100%. AQ+ kit performance with saliva was in the range of the World Health Organization recommended value.

Conclusion

xOur findings indicate that the saliva specimen can be used as an alternative and less invasive to NPs for quick and reliable SARS-CoV-2 antigen detection.

Are COVID-19 patients given adequate instructions about toothbrush hygiene? A cross-sectional study

OBJECTIVE

The aim of this study was to evaluate toothbrush hygienic practices, whether subjects with a positive COVID-19 test received instructions about toothbrush hygiene, and to determine if carriers of SARS CoV-2 were assigned separate bathrooms during home isolation.

METHODS

Data were collected by an anonymous online questionnaire. Variables of interest included toothbrush hygiene practices, receiving instructions on toothbrush handling if tested positive for COVID-19, and being assigned separate bathrooms during home isolation.

RESULTS

From November 2020 through April 2021; 755 responded (472 [62.5%] females, 269 [35.6%] males, 14 [1.85%] did not specify their gender). 14 (4.1%) of 341 respondents who reported a positive result of a COVID-19 test received instructions about how to maintain their toothbrush during home isolation. The majority of subjects (74.4%) reported the use of water to wet their toothbrush before brushing, this practice was significantly more common among young subjects (p < 0.001). 58.6% wash all parts of the toothbrush after use while 38.8% wash the head of the toothbrush, and 1.6% place the toothbrush in an antiseptic. 53% used separate bathrooms during isolation, this was significantly associated with age group (p = 0.006) and higher monthly income (p = 0.02).

CONCLUSIONS

The majority of participants with a positive result of the COVID-19 test were not given explicit instructions about toothbrush handling. Less than half reported good toothbrush hygienic practices. Higher monthly income was significantly associated with using a separate bathroom during home isolation. Providing explicit instructions about toothbrush hygiene is recommended to reduce the spread of contagious diseases such as COVID-19.

The Nexus Between COVID-19 Factors and Air Pollution

Background and Objective

There have been significant effects of the current coronavirus-19 (COVID-19) infection outbreak on many facets of everyday life, particularly the environment. Despite the fact that a number of studies have already been published on the topic, an analysis of those studies' findings on COVID-19's effects on environmental pollution is still lacking. The goal of the research is to look into greenhouse gas emissions and air pollution in Bangladesh when COVID-19 is under rigorous lockdown. The specific drivers of the asymmetric relationship between air pollution and COVID-19 are being investigated.

Methods

The nonlinear relationship between carbon dioxide ( C O 2 ) emissions, fine particulate matter ( P M 2 . 5 ) , and COVID-19, as well as its precise components, are also being investigated. To examine the asymmetric link between COVID-19 factors on C O 2 emissions and P M 2 . 5 , we employed the nonlinear autoregressive distributed lag (NARDL) model. Daily positive cases and daily confirmed death by COVID-19 are considered the factors of COVID-19, with lockdown as a dummy variable.

Results

The bound test confirmed the existence of long-run and short-run relationships between variables. Bangladesh's strict lockdown, enforced in reaction to a surge of COVID-19 cases, reduced air pollution and dangerous gas emissions, mainly C O 2 , according to the dynamic multipliers graph.

Peptide nucleic acid and antifouling peptide based biosensor for the non-fouling detection of COVID-19 nucleic acid in saliva

The electrochemical biosensor with outstanding sensitivity and low cost is regarded as a viable alternative to current clinical diagnostic techniques for various disease biomarkers. However, their actual analytical use in complex biological samples is severely hampered due to the biofouling, as they are also highly sensitive to nonspecific adsorption on the sensing interfaces. Herein, we have constructed a non-fouling electrochemical biosensor based on antifouling peptides and the electroneutral peptide nucleic acid (PNA), which was used as the recognizing probe for the specific binding of the viral RNA of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Different from the negatively charged DNA probes that will normally weaken the biosensors' antifouling capabilities owing to the charge attraction of positively charged biomolecules, the neutral PNA probe will generate no side-effects on the biosensor. The biosensor demonstrated remarkable sensitivity in detecting SARS-CoV-2 viral RNA, possessing a broad linear range (1.0 fM - 1.0 nM) and a detection limit down to 0.38 fM. Furthermore, the sensing performance of the constructed electrochemical biosensor in human saliva was nearly similar to that in pure buffer, indicating satisfying antifouling capability. The combination of PNA probes with antifouling peptides offered a new strategy for the development of non-fouling sensing systems capable of assaying trace disease biomarkers in complicated biological media.

Smartphone-based corona virus detection using saliva: A mini-review

During the ongoing worldwide epidemic, SARS-CoV-2 has infected millions of individuals and taken the lives of numerous victims. It is clear that early detection of infected individuals, especially asymptomatic carriers, is possible with the development of innovative analytical tools for rapid identification of COVID-19 present in nasopharyngeal swabs, serum, and saliva. The saliva, as a diagnostic sample, can be easily collected by the patient with almost no discomfort and needs specialized healthcare personnel to manage, which reduces the risks for the operator. Moreover, smartphone-based sensing systems are one of the most attractive techniques that can speed up the detection time of COVID-19 agents without the need for professional staff and clinical centers. In this review, recent advances in precise salivary-based SARS-CoV-2 diagnosis using smartphones via viral RNA detection, antibody identification, and viral antigen identification were summarized. Finally, the conclusion and future perspective of this field are described in brief.

The Dark Side of Interpersonal Touch: Physical Contact Leads to More Non-compliance With Preventive Measures to COVID-19

Following preventive measures is crucial for slowing the rate of COVID-19 spread. To date, most research has focused on the role of individual differences and personality in compliance with preventive measures to COVID-19. Building on findings that interpersonal touch instills a feeling of security, we propose that interpersonal touching behavior, an underexplored factor tied to social interaction, leads to more breaches of coronavirus restrictions by inducing security feelings. In a lab experiment (Experiment 1) and a field study (Experiment 2), we demonstrated that a female experimenter's fleeting and comforting pat on the shoulder made people less willing to abide by preventive measures in their self-report and actual behavior. Further, we excluded a potential alternative explanation that touch intervention by the experimenter presents the defiance of COVID-19 rules because the effect cannot be observed when the touch consists of a handshake rather than a comforting pat on the shoulder (Experiment 3). Finally, consistent with our theoretical perspective, the results revealed that sense of security mediated the effect of interpersonal touch on violation of instructions to follow coronavirus precautions. Taken together, interpersonal touch not only enhances trust and security, but also can push people away from health guidelines.

Progress in salivary glands: Endocrine glands with immune functions

The production and secretion of saliva is an essential function of the salivary glands. Saliva is a complicated liquid with different functions, including moistening, digestion, mineralization, lubrication, and mucosal protection. This review focuses on the mechanism and neural regulation of salivary secretion, and saliva is secreted in response to various stimuli, including odor, taste, vision, and mastication. The chemical and physical properties of saliva change dynamically during physiological and pathophysiological processes. Moreover, the central nervous system modulates salivary secretion and function via various neurotransmitters and neuroreceptors. Smell, vision, and taste have been investigated for the connection between salivation and brain function. The immune and endocrine functions of the salivary glands have been explored recently. Salivary glands play an essential role in innate and adaptive immunity and protection. Various immune cells such as B cells, T cells, macrophages, and dendritic cells, as well as immunoglobins like IgA and IgG have been found in salivary glands. Evidence supports the synthesis of corticosterone, testosterone, and melatonin in salivary glands. Saliva contains many potential biomarkers derived from epithelial cells, gingival crevicular fluid, and serum. High level of matrix metalloproteinases and cytokines are potential markers for oral carcinoma, infectious disease in the oral cavity, and systemic disease. Further research is required to monitor and predict potential salivary biomarkers for health and disease in clinical practice and precision medicine.

[Developments in Research on Salivary Biomarkers in the Diagnosis of Systemic Diseases]

Saliva, an important biological fluid secreted by oral glands, serves multiple functions. It performs cleaning and protective functions for oral tissues, safeguarding against biological, mechanical and chemical stimuli, while allowing for the sensory perception of taste and temperature. It is also responsible for the preliminary digestion of food. These functions and properties of saliva are attributed to the presence of electrolytes, buffers, proteins, glycoproteins, and lipids in saliva. Recent studies have found that saliva contains biomarkers that are closely connected with the pathophysiological status of the human body, suggesting that saliva makes an ideal biological fluid for drug monitoring and biomarker screening. Therefore, salivary biomarkers can be used as an instrument for physical monitoring and localization of the occurrence of diseases, thereby accomplishing early diagnosis of diseases and assessment of the overall health status of patients. However, the actual application of salivary biomarkers in the diagnosis and treatment of systemic diseases is still not widely available, and the establishment of evaluation criteria and the exploration of its mechanism are not sufficiently investigated. Herein, we reviewed the latest research findings on applying the salivary biomarkers in the diagnosis of systemic diseases.

Hand instrumentation provides improved tissue response over ultrasonic scaler and substantiates safe dental practice: An in vivo study in rats

OBJECTIVE

The aim of this study was to evaluate the effectiveness of hand debridement (HD) versus ultrasonic dental scaler (UDS) for the treatment of experimental periodontitis (EP) in rats.

MATERIAL AND METHODS

Thirty 3-month-old male rats were used. EP was induced around the mandibular first molars (right and left). Seven days after induction, the treatments with either HD (n = 30) or UDS (n = 30) were randomly performed in each molar. Euthanasia were performed at 7, 15, and 30 days after treatment. Histometric (percentage of bone in the furcation [PBF]), histopathological, and immunohistochemical (for detection of tartrate-resistant acid phosphatase [TRAP] and osteocalcin [OCN]). Parametric data (PBF and TRAP) was analyzed by One-way ANOVA followed by Tukey's post-test. OCN was analyzed by Kruskal-Wallis followed by Student-Newman-Keuls post-test. The level of significance was 5%.

RESULTS

Group HD presented higher PBF and lower TRAP-immunolabeling at 30 days as compared with UDS in the same period (p≤0.05). Group HD presented higher OCN immunolabeling at 30 days as compared with 7 and 15 days (p≤0.05). Persistent and exacerbated inflammatory process was observed in some specimens from group UDS at 30 days, as well as the bone trabeculae presented irregular contour, surrounded by many active osteoclasts.

CONCLUSION

Nonsurgical periodontal therapy with HD resulted in higher PBF and lower expression of TRAP as compared with UDS. Also, HD increased the expression of OCN over time.

Characterization of Ag-Ion Releasing Zeolite Filled 3D Printed Resins

There has been profound growth in the use of 3D printed materials in dentistry in general, including orthodontics. The opportunity to impart antimicrobial properties to 3D printed parts from existing resins requires the capability of forming a stable colloid incorporating antimicrobial fillers. The objective of this research was to characterize a colloid consisting of a 3D printable resin mixed with Ag-ion releasing zeolites and fumed silica to create 3D printed parts with antiviral properties. The final composite was tested for antiviral properties against SARS-CoV-2 and HIV-1. Antiviral activity was measured in terms of the half-life of SARS-CoV-2 and HIV-1 on the composite surface. The inclusion of the zeolite did not interfere with the kinetics measured on the surface of the ATR crystal. While the depth of cure, measured following ISO4049 guidelines, was reduced from 3.8 mm to 1.4 mm in 5 s, this greatly exceeded the resolution required for 3D printing. The colloid was stable for at least 6 months and the rheological behavior was dependent upon the fumed silica loading. The inclusion of zeolites and fumed silica significantly increased the flexural strength of the composite as measured by a 3 point bend test. The composite released approximately 2500 μg/L of silver ion per gram of composite as determined by potentiometry. There was a significant reduction of the average half-life of SARS-CoV-2 (1.9 fold) and HIV-1 (2.7 fold) on the surface of the composite. The inclusion of Ag-ion releasing zeolites into 3D-printable resin can result in stable colloids that generate composites with improved mechanical properties and antiviral properties.

Salivary Dangers and their Resolution

In China, when people have a meal together, it is certainly possible for individuals to order a personal dish that is not for sharing with others. But it is far more common for food to be exchanged directly between hands, between hands-and-mouths and, as I will describe shortly, effectively between mouths. This describes the circumstance when consumers directly eat food from a shared dish, with the effect that they encounter each other's saliva. This mode of consumption is called gong can. On the face of it, it seems foolhardy to continue to eat together in such a way during a pandemic that travels between bodies through connecting droplets, like saliva, especially when other forms of eating together are available. Why is such a mode preferred during the COVID-19 pandemic? What makes it safe?

Survival of human coronavirus 229E at different temperatures on various food-contact surfaces and food and under simulated digestive conditions

The COVID-19 pandemic caused by SARS-CoV-2 has had a major impact on human health and the global economy. Various transmission possibilities of SARS-CoV-2 have been proposed, such as the surface of food in the cold chain and food packaging, as well as the fecal-oral route, although person-to-person contact via droplets and aerosols has been confirmed as the main route of transmission. This study evaluated the survivability of HCoV-229E, a SARS-CoV-2 surrogate, in suspension, on food-contact surfaces and on food at various temperatures, and in simulated digestive fluids by TCID₅₀ assay. In suspension, HCoV-229E survived after 5 days at 20 °C with a 3.69 log reduction, after 28 days at 4 °C with a 3.07 log reduction, and after 12 weeks at -20 °C with a 1.18 log reduction. On food-contact surfaces, HCoV-229E was not detected on day 3 on stainless steel (SS), plastic (LDPE), and silicone rubber (SR) at 20 °C with a 3.28, 3.24 and 3.28 log reduction, respectively, and survived after 28 days on SS and LDPE at 4 °C with a 3.13 and 2.88 log reduction, respectively, and survived after 12 weeks on SS, LDPE, and SR at -20 °C with a 1.92, 1.32 and 1.99 log reduction, respectively. On food, HCoV-229E was not detected on day 3 on lettuce and day 4 on chicken breast and salmon at 20 °C with a 3.61, 3.26 and 3.08 log reduction, respectively, and on day 14 on lettuce and day 21 on chicken breast and salmon at 4 °C with a 3.88, 3.44 and 3.56 log reduction, respectively. The virus remained viable for 12 weeks in all foods at -20 °C with 2-2.47 log reduction. In addition, in simulated digestive fluid experiments, HCoV-229E was relatively resistant in simulated salivary fluid (SSF; pH 7, 5), fed state simulated gastric fluid (FeSSGF; pH 3, 5, 7), and fasted state simulated intestinal fluid (FaSSIF; pH 7). However, the virus was less tolerant in fasted state simulated gastric fluid (FaSSGF; pH 1.6) and fed state simulated intestinal fluid (FeSSIF; pH 5). Therefore, this study suggested that HCoV-229E remained infectious on various food-contact surfaces and foods; in particular, it survived longer at lower temperatures and survived depending on the pH of the simulated digestive fluid.

Virucidal activity in vitro of mouthwashes against a feline coronavirus type II

Transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can occur through saliva and aerosol droplets deriving from the upper aerodigestive tract during coughing, sneezing, talking, and even during oral inspection or dental procedures. The aim of this study was to assess in vitro virucidal activity of commercial and experimental mouthwashes against a feline coronavirus (FCoV) strain. Commercial and experimental (commercial-based products with addition of either sodium dodecyl sulfate (SDS) or thymus vulgaris essential oil (TEO) at different concentrations) mouthwashes were placed in contact with FCoV for different time intervals, that is, 30 s (T30), 60 s (T60), and 180 s (T180); subsequently, the virus was titrated on Crandell Reese Feline Kidney cells. An SDS-based commercial mouthwash reduced the viral load by 5 log10 tissue culture infectious dose (TCID)₅₀ /50 µl at T30 while a cetylpyridinium (CPC)-based commercial mouthwash was able to reduce the viral titer of 4.75 log10 at T60. Furthermore, five experimental mouthwashes supplemented with SDS reduced the viral titer by 4.75-5 log10 according to a dose- (up to 4 mM) and time-dependent fashion.

Factors Related to the Intention to Use Dental Care by Industrial Workers Due to COVID-19: Application of Anderson Model and Planned Behavior Theory

The COVID-19 pandemic has affected medical and dental care in Korea. This study aimed to investigate the factors influencing the intention to use dental care in industrial workers, an economically active population. An online questionnaire survey was completed by 301 industrial workers. Stress and anxiety to viral epidemics-6 (SAVE-6), attitude, subjective norm, perceived behavior control, and intention to use dental care, based on the theory of planned behavior (TPB), were measured. Predisposing, enabling, and need factors based on the Andersen model were measured as control variables for influencing factors. In the final hierarchical multiple regression analysis, the most significant relevant factors affecting intention to use dental care were attitude (β = 0.598, p < 0.001), followed by experience of dental clinic visits (β = 0.237, p < 0.001), subjective norm (β = 0.125, p < 0.001), perceived behavior control (β = 0.114, p = 0.004), SAVE-6 (β = -0.073, p = 0.025), and gingival bleeding (β = 0.062, p = 0.029). Dental care use decreased to 58.5%, and socio-psychological factors based on TPB were closely associated with the intention to use dental care. Therefore, awareness must be raised regarding oral health practices to increase the use of dental care among industrial workers.

Tobacco product use and the risks of SARS-CoV-2 infection and COVID-19: current understanding and recommendations for future research

Heterogeneity in the clinical presentation of SARS-CoV-2 infection and COVID-19 progression underscores the urgent need to identify individual-level susceptibility factors that affect infection vulnerability and disease severity. Tobacco product use is a potential susceptibility factor. In this Personal View, we provide an overview of the findings of peer-reviewed, published studies relating tobacco product use to SARS-CoV-2 infection and COVID-19 outcomes, with most studies focusing on cigarette smoking in adults. Findings pertaining to the effects of tobacco product use on the incidence of SARS-CoV-2 infection are inconsistent. However, evidence supports a role for cigarette smoking in increasing the risk of poor COVID-19 outcomes, including hospital admission, progression in disease severity, and COVID-19-related mortality. We discuss the potential effects of tobacco use behaviour on SARS-CoV-2 transmission and infection, and highlight the pathophysiological changes associated with cigarette smoking that could promote SARS-CoV-2 infection and increased disease severity. We consider the biological mechanisms by which nicotine and other tobacco product constituents might affect immune and inflammatory responses to SARS-CoV-2 infection. Finally, we identify current knowledge gaps and suggest priorities for research to address acute and post-acute health outcomes of COVID-19 during and after the pandemic.

Debulking different Corona (SARS-CoV-2 delta, omicron, OC43) and Influenza (H1N1, H3N2) virus strains by plant viral trap proteins in chewing gums to decrease infection and transmission

Because oral transmission of SARS-CoV-2 is 3-5 orders of magnitude higher than nasal transmission, we investigated debulking of oral viruses using viral trap proteins (CTB-ACE2, FRIL) expressed in plant cells, delivered through the chewing gum. In omicron nasopharyngeal (NP) samples, the microbubble count (based on N-antigen) was significantly reduced by 20 μg of FRIL (p < 0.0001) and 0.925 μg of CTB-ACE2 (p = 0.0001). Among 20 delta or omicron NP samples, 17 had virus load reduced below the detection level of spike protein in the RAPID assay, after incubation with the CTB-ACE2 gum powder. A dose-dependent 50% plaque reduction with 50-100 ng FRIL or 600-800 μg FRIL gum against Influenza strains H1N1, H3N2, and Coronavirus HCoV-OC43 was observed with both purified FRIL, lablab bean powder or gum. In electron micrographs, large/densely packed clumps of overlapping influenza particles and FRIL protein were observed. Chewing simulator studies revealed that CTB-ACE2 release was time/dose-dependent and release was linear up to 20 min chewing. Phase I/II placebo-controlled, double-blinded clinical trial (IND 154897) is in progress to evaluate viral load in saliva before or after chewing CTB-ACE2/placebo gum. Collectively, this study advances the concept of chewing gum to deliver proteins to debulk oral viruses and decrease infection/transmission.

Preprocedural mouth rinses for preventing transmission of infectious diseases through aerosols in dental healthcare providers

BACKGROUND

Aerosols and spatter are generated in a dental clinic during aerosol-generating procedures (AGPs) that use high-speed hand pieces. Dental healthcare providers can be at increased risk of transmission of diseases such as tuberculosis, measles and severe acute respiratory syndrome (SARS) through droplets on mucosae, inhalation of aerosols or through fomites on mucosae, which harbour micro-organisms. There are ways to mitigate and contain spatter and aerosols that may, in turn, reduce any risk of disease transmission. In addition to personal protective equipment (PPE) and aerosol-reducing devices such as high-volume suction, it has been hypothesised that the use of mouth rinse by patients before dental procedures could reduce the microbial load of aerosols that are generated during dental AGPs.

OBJECTIVES

To assess the effects of preprocedural mouth rinses used in dental clinics to minimise incidence of infection in dental healthcare providers and reduce or neutralise contamination in aerosols.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 4 February 2022.

SELECTION CRITERIA

We included randomised controlled trials and excluded laboratory-based studies. Study participants were dental patients undergoing AGPs. Studies compared any preprocedural mouth rinse used to reduce contaminated aerosols versus placebo, no mouth rinse or another mouth rinse. Our primary outcome was incidence of infection of dental healthcare providers and secondary outcomes were reduction in the level of contamination of the dental operatory environment, cost, change in mouth microbiota, adverse events, and acceptability and feasibility of the intervention.

DATA COLLECTION AND ANALYSIS

Two review authors screened search results, extracted data from included studies, assessed the risk of bias in the studies and judged the certainty of the available evidence. We used mean differences (MDs) and 95% confidence intervals (CIs) as the effect estimate for continuous outcomes, and random-effects meta-analysis to combine data  MAIN RESULTS:  We included 17 studies with 830 participants aged 18 to 70 years. We judged three trials at high risk of bias, two at low risk and 12 at unclear risk of bias.  None of the studies measured our primary outcome of the incidence of infection in dental healthcare providers.  The primary outcome in the studies was reduction in the level of bacterial contamination measured in colony-forming units (CFUs) at distances of less than 2 m (intended to capture larger droplets) and 2 m or more (to capture droplet nuclei from aerosols arising from the participant's oral cavity). It is unclear what size of CFU reduction represents a clinically significant amount. There is low- to very low-certainty evidence that chlorhexidine (CHX) may reduce bacterial contamination, as measured by CFUs, compared with no rinsing or rinsing with water. There were similar results when comparing cetylpyridinium chloride (CPC) with no rinsing and when comparing CPC, essential oils/herbal mouthwashes or boric acid with water. There is very low-certainty evidence that tempered mouth rinses may provide a greater reduction in CFUs than cold mouth rinses. There is low-certainty evidence that CHX may reduce CFUs more than essential oils/herbal mouthwashes. The evidence for other head-to-head comparisons was limited and inconsistent.  The studies did not provide any information on costs, change in micro-organisms in the patient's mouth or adverse events such as temporary discolouration, altered taste, allergic reaction or hypersensitivity. The studies did not assess acceptability of the intervention to patients or feasibility of implementation for dentists.  AUTHORS' CONCLUSIONS: None of the included studies measured the incidence of infection among dental healthcare providers. The studies measured only reduction in level of bacterial contamination in aerosols. None of the studies evaluated viral or fungal contamination. We have only low to very low certainty for all findings. We are unable to draw conclusions regarding whether there is a role for preprocedural mouth rinses in reducing infection risk or the possible superiority of one preprocedural rinse over another. Studies are needed that measure the effect of rinses on infectious disease risk among dental healthcare providers and on contaminated aerosols at larger distances with standardised outcome measurement.

Role of Saliva as a Non-Invasive Diagnostic Method for Detection of COVID-19

SARS coronavirus2 is the primary cause of new Coronavirus illness (COVID-19) (SARS- COV-2). Today, COVID-19 is a global epidemic. Coronavirus illness may be diagnosed using a variety of approaches. The gold standard is RT-PCR, which is used in all of these assays. Swabs from the nose, pharynx, or mouth are the most often used sampling methods for coronavirus detection. For COVID-19 testing, saliva may be utilized as an alternate sample. When compared to a nasopharyngeal swab, saliva samples have a number of advantages and disadvantages. Saliva has also been reviewed as a non-invasive diagnostic tool for the detection of COVID-19. The affordability of the salivary diagnostic process makes it an effective process for detecting the COVID-19 viruses. The researchers have found that salivary diagnostic processes have greater chances of success than other processes of Coronavirus detection. However, healthcare professionals need to make positive changes to their working processes to ensure the sustainability of the salivary diagnosis processes.

Redefining aerosol in dentistry during COVID-19 pandemic

The corona virus malady 2019 (COVID-19) pandemic has rekindled the well established argument regarding the role of dental aerosol in transference of severe acute respiratory syndrome corona virus 2 (SARS-CoV-2). Aerosols and droplets are generated amid innumerable dental procedures. With the commencement of the COVID-19 pandemic droplet, a review of the infection/disease control strategies for aerosols is required. We do not know where this pandemic is directed. We do not have conclusive evidence for an optimal management strategy. Every day brings in varying information, so recognizing the hazard created by aerosols will help diminish the probability of infection transfer at the time of dental procedures. Hence, the author assessed the evidence-based medical and dental literature in relation to "aerosol' that documented the source of transmission of aerosol through various potential routes, addressed the risk potential to patients and the dental team, and assessed the additional measures that might minimize the viral transmission if regularly adopted. In this article, the author evaluated and compiled dental guidelines by various countries and various health-care associations in context to aerosol-generating procedures and has made recommendations for the restriction of dental aerosols and splatter in routine dental practice.

Saliva as a propitious diagnostic biofluid, biomarker, and bodies first line of defense against COVID-19: A review

This review aims to recognize the role of saliva not just as a transmitting agent of COVID 19, but also comprehend its role in the diagnosis, and as a biomarker. A systematic literature search was performed in the PubMed database and eligible studies were included if they addressed the key issues i.e saliva as a diagnostic aid. As of January 10, 2021, a total of 309 articles across the PubMed database were identified of which 28 studies met the inclusion criteria. They were carefully examined for the type of study, sample size, parameters used, sample collection technique, and conclusions drawn. Diagnostic properties of saliva, the role of ACE 2 receptors, antibody formation ability, and antiviral characteristics were also explored. Comparisons among methods of sample collection like nasopharyngeal swabs and oropharyngeal swabs to saliva were also investigated. The observations and important deductions among the different studies were compared. Results indicated that saliva could be a reliable and financially viable option in both testing viral titers as well as marking for bio analytes due to its propitious specificity and sensitivity results reported in most of the studies. However, the inferences drawn from many of these studies should be interpreted with caution due to small sample sizes, inadequate detailing on the sample handling, laboratory processing, and rush in Corona-related publication. Scientific research with larger sample sizes, in diverse populations and age groups, at different phases of disease progression of COVID-19 are essential to reach any conclusion regarding its multi-facet use in the future.

SARS-CoV-2 variants of concern Alpha and Delta show increased viral load in saliva

BACKGROUND

Higher viral loads in SARS-CoV-2 infections may be linked to more rapid spread of emerging variants of concern (VOC). Rapid detection and isolation of cases with highest viral loads, even in pre- or asymptomatic individuals, is essential for the mitigation of community outbreaks.

METHODS AND FINDINGS

In this study, we analyze Ct values from 1297 SARS-CoV-2 positive patient saliva samples collected at the Clemson University testing lab in upstate South Carolina. Samples were identified as positive using RT-qPCR, and clade information was determined via whole genome sequencing at nearby commercial labs. We also obtained patient-reported information on symptoms and exposures at the time of testing. The lowest Ct values were observed among those infected with Delta (median: 22.61, IQR: 16.72-28.51), followed by Alpha (23.93, 18.36-28.49), Gamma (24.74, 18.84-30.64), and the more historic clade 20G (25.21, 20.50-29.916). There was a statistically significant difference in Ct value between Delta and all other clades (all p.adj<0.01), as well as between Alpha and 20G (p.adj<0.05). Additionally, pre- or asymptomatic patients (n = 1093) showed the same statistical differences between Delta and all other clades (all p.adj<0.01); however, symptomatic patients (n = 167) did not show any significant differences between clades. Our weekly testing strategy ensures that cases are caught earlier in the infection cycle, often before symptoms are present, reducing this sample size in our population.

CONCLUSIONS

COVID-19 variants Alpha and Delta have substantially higher viral loads in saliva compared to more historic clades. This trend is especially observed in individuals who are pre- or asymptomatic, which provides evidence supporting higher transmissibility and more rapid spread of emerging variants. Understanding the viral load of variants spreading within a community can inform public policy and clinical decision making.

Debulking SARS-CoV-2 in saliva using angiotensin converting enzyme 2 in chewing gum to decrease oral virus transmission and infection

To advance a novel concept of debulking virus in the oral cavity, the primary site of viral replication, virus-trapping proteins CTB-ACE2 were expressed in chloroplasts and clinical-grade plant material was developed to meet FDA requirements. Chewing gum (2 g) containing plant cells expressed CTB-ACE2 up to 17.2 mg ACE2/g dry weight (11.7% leaf protein), have physical characteristics and taste/flavor like conventional gums, and no protein was lost during gum compression. CTB-ACE2 gum efficiently (>95%) inhibited entry of lentivirus spike or VSV-spike pseudovirus into Vero/CHO cells when quantified by luciferase or red fluorescence. Incubation of CTB-ACE2 microparticles reduced SARS-CoV-2 virus count in COVID-19 swab/saliva samples by >95% when evaluated by microbubbles (femtomolar concentration) or qPCR, demonstrating both virus trapping and blocking of cellular entry. COVID-19 saliva samples showed low or undetectable ACE2 activity when compared with healthy individuals (2,582 versus 50,126 ΔRFU; 27 versus 225 enzyme units), confirming greater susceptibility of infected patients for viral entry. CTB-ACE2 activity was completely inhibited by pre-incubation with SARS-CoV-2 receptor-binding domain, offering an explanation for reduced saliva ACE2 activity among COVID-19 patients. Chewing gum with virus-trapping proteins offers a general affordable strategy to protect patients from most oral virus re-infections through debulking or minimizing transmission to others.

Systematic evaluating and modeling of SARS-CoV-2 UVC disinfection

The ongoing COVID-19 global pandemic has necessitated evaluating various disinfection technologies for reducing viral transmission in public settings. Ultraviolet (UV) radiation can inactivate pathogens and viruses but more insight is needed into the performance of different UV wavelengths and their applications. We observed greater than a 3-log reduction of SARS-CoV-2 infectivity with a dose of 12.5 mJ/cm² of 254 nm UV light when the viruses were suspended in PBS, while a dose of 25 mJ/cm² was necessary to achieve a similar reduction when they were in an EMEM culture medium containing 2%(v/v) FBS, highlighting the critical effect of media in which the virus is suspended, given that SARS-CoV-2 is always aerosolized when airborne or deposited on a surface. It was found that SARS-CoV-2 susceptibility (a measure of the effectiveness of the UV light) in a buffer such as PBS was 4.4-fold greater than that in a cell culture medium. Furthermore, we discovered the attenuation of UVC disinfection by amino acids, vitamins, and niacinamide, highlighting the importance of determining UVC dosages under a condition close to aerosols that wrap the viruses. We developed a disinfection model to determine the effect of the environment on UVC effectiveness with three different wavelengths, 222 nm, 254 nm, and 265 nm. An inverse correlation between the liquid absorbance and the viral susceptibility was observed. We found that 222 nm light was most effective at reducing viral infectivity in low absorbing liquids such as PBS, whereas 265 nm light was most effective in high absorbing liquids such as cell culture medium. Viral susceptibility was further decreased in N95 masks with 222 nm light being the most effective. The safety of 222 nm was also studied. We detected changes to the mechanical properties of the stratum corneum of human skins when the 222 nm accumulative exposure exceeded 50 J/cm².The findings highlight the need to evaluate each UV for a given application, as well as limiting the dose to the lowest dose necessary to avoid unnecessary exposure to the public.

The Impact of COVID-19 Pandemic on Halting Sustainable Development in the Colca y Volcanes de Andagua UNESCO Global Geopark in Peru—Prospects and Future

Events, such as the COVID-19 pandemic, that rapidly impact global communication and travel have significant consequences for the tourism industry, which is one of the pillars of global development. We assess the impacts of the COVID-19 crisis on the Colca y Volcanes de Andagua UNESCO Global Geopark in Peru. The Colca y Volcanes de Andagua Geopark was established immediately prior to the pandemic in October 2019. The instability of the government in Peru during the pandemic and the difficult living conditions in the high Andes, such as the lack of drinking water, cleaning agents, medical care, and the high levels of poverty, particularly in the geopark region, has contributed to the significantly high COVID-19 infection rates. In addition, detrimental impacts faced by the local community are a direct result of a reduction in travellers to the area due to legislative restrictions, which have had negative consequences on the local tourism industry. There is an urgent need for the recovery of the local tourism industry to prevent the permanent closure of tourism facilities and to minimise poverty rates.

SARS-CoV-2 variants of concern Alpha and Delta show increased viral load in saliva

BACKGROUND

Higher viral loads in SARS-CoV-2 infections may be linked to more rapid spread of emerging variants of concern (VOC). Rapid detection and isolation of cases with highest viral loads, even in pre- or asymptomatic individuals, is essential for the mitigation of community outbreaks.

METHODS AND FINDINGS

In this study, we analyze Ct values from 1297 SARS-CoV-2 positive patient saliva samples collected at the Clemson University testing lab in upstate South Carolina. Samples were identified as positive using RT-qPCR, and clade information was determined via whole genome sequencing at nearby commercial labs. We also obtained patient-reported information on symptoms and exposures at the time of testing. The lowest Ct values were observed among those infected with Delta (median: 22.61, IQR: 16.72-28.51), followed by Alpha (23.93, 18.36-28.49), Gamma (24.74, 18.84-30.64), and the more historic clade 20G (25.21, 20.50-29.916). There was a statistically significant difference in Ct value between Delta and all other clades (all p.adj<0.01), as well as between Alpha and 20G (p.adj<0.05). Additionally, pre- or asymptomatic patients (n=1093) showed the same statistical differences between Delta and all other clades (all p.adj<0.01); however, symptomatic patients (n=167) did not show any significant differences between clades. Our weekly testing strategy ensures that cases are caught earlier in the infection cycle, often before symptoms are present, reducing this sample size in our population.

CONCLUSIONS

COVID-19 variants Alpha and Delta have substantially higher viral loads in saliva compared to more historic clades. This trend is especially observed in individuals who are pre- or asymptomatic, which provides evidence supporting higher transmissibility and more rapid spread of emerging variants. Understanding the viral load of variants spreading within a community can inform public policy and clinical decision making.

Temperature-adjustable F-carbon nanofiber/carbon fiber nanocomposite fibrous masks with excellent comfortability and anti-pathogen functionality

Wearing surgical masks remains the most effective protective measure against COVID-19 before mass vaccination, but insufficient comfortability and low antibacterial/antiviral activities accelerate the replacement frequency of surgical masks, resulting in large amounts of medical waste. To solve this problem, we report new nanofiber membrane masks with outstanding comfortability and anti-pathogen functionality prepared using fluorinated carbon nanofibers/carbon fiber (F-CNFs/CF). This was used to replace commercial polypropylene (PP) nonwovens as the core layer of face masks. The through-plane and in-plane thermal conductivity of commercial PP nonwovens were only 0.12 and 0.20 W/m K, but the F-CNFs/CF nanofiber membranes reached 0.62 and 5.23 W/m K, which represent enhancements of 380% and 2523%, respectively. The surface temperature of the PP surgical masks was 23.9 ℃ when the wearing time was 15 min, while the F-CNFs/CF nanocomposite fibrous masks reached 27.3 ℃, displaying stronger heat dissipation. Moreover, the F-CNFs/CF nanofiber membranes displayed excellent electrical conductivity and produced a high-temperature layer that killed viruses and bacteria in the masks. The surface temperature of the F-CNFs/CF nanocomposite fibrous masks reached 69.2 ℃ after being connected to a portable power source for 60 s. Their antibacterial rates were 97.9% and 98.6% against E. coli and S. aureus, respectively, after being connected to a portable power source for 30 min.

UV-C Light-Based Surface Disinfection: Analysis of Its Virucidal Efficacy Using a Bacteriophage Model

Background: The reprocessing of medical devices has become more complex due to increasing hygiene requirements. Previous studies showed satisfactory bactericidal disinfection effects of UV-C light in rigid and flexible endoscopes. Especially in the context of the current COVID-19 pandemic, virucidal properties are of high importance. In the present study, the virucidal efficacy of UV-C light surface disinfection was analyzed. Methods: MS-2 bacteriophages were applied to the test samples and irradiated by UV-C light using the UV Smart D25 device; unirradiated test samples were used as controls. A dilution series of the samples was mixed with 1 × 108 Escherichia coli and assayed. Results: 8.6 × 1012 pfu could be harvested from the unprocessed test samples. In the control group without UV-C exposure, a remaining contamination of 1.2 × 1012 pfu was detected, resulting in a procedural baseline reduction rate with a LOG10 reduction factor of 0.72. The LOG10 reduction factor was found to be 3.0 after 25 s of UV-C light exposure. After 50 and 75 s of UV-C radiation LOG10 reduction factors 4.2 and 5.9, respectively, were found, with all reductions being statistically significantly different to baseline. Conclusions: The tested UV system seems to provide a significant virucidal effect after a relatively short irradiation time.

Virucidal Activity of Different Mouthwashes against the Salivary Load of SARS-CoV-2: A Narrative Review

The saliva of COVID-19-confirmed patients presents a high viral load of the virus. Aerosols generated during medical and dental procedures can transport the virus and are a possible causative agent of cross-infection. Since the onset of the pandemic, numerous investigations have been attempting to mitigate the risk of transmission by reducing the viral load in saliva using preprocedural mouthwashes. This study aims to review the most up-to-date in vitro and in vivo studies investigating the efficacy of different mouthwashes on reducing the salivary viral load of SARS-CoV-2, giving particular attention to the most recent randomized control trials published.

Small form factor flow virometer for SARS-CoV-2

Current diagnostics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection heavily rely on reverse transcription-polymerase chain reaction (RT-PCR) or on rapid antigen detection tests. The former suffers from long time-to-result and high cost while the latter from poor sensitivity. Therefore, it is crucial to develop rapid, sensitive, robust, and inexpensive methods for SARS-CoV-2 testing. Herein, we report a novel optofluidic technology, a flow-virometry reader (FVR), for fast and reliable SARS-CoV-2 detection in saliva samples. A small microfluidic chip together with a laser-pumped optical head detects the presence of viruses tagged with fluorescent antibodies directly from saliva samples. The technology has been validated using clinical samples with high sensitivity (91.2%) and specificity (90%). Thanks also to its short time-to-result (<30 min) and small size (25 × 30 × 13 cm), which can be further reduced in the future, it is a strong alternative to existing tests, especially for point-of-care (POC) and low resource settings.

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

Introduction. The importance of human saliva in aerosol-based transmission of SARS-CoV-2 is now widely recognized. However, little is known about the efficacy of virucidal mouthwash formulations against emergent SARS-CoV-2 variants of concern and in the presence of saliva.

Hypothesis. Mouthwashes containing virucidal actives will have similar inactivation effects against multiple SARS-CoV-2 variants of concern and will retain efficacy in the presence of human saliva.

Aim. To examine in vitro efficacy of mouthwash formulations to inactivate SARS-CoV-2 variants.

Methodology. Inactivation of SARS-CoV-2 variants by mouthwash formulations in the presence or absence of human saliva was assayed using ASTM International Standard E1052-20 methodology.

Results. Appropriately formulated mouthwashes containing 0.07 % cetylpyridinium chloride but not 0.2 % chlorhexidine completely inactivated SARS-CoV-2 (USA-WA1/2020, Alpha, Beta, Gamma, Delta) up to the limit of detection in suspension assays. Tests using USA-WA1/2020 indicates that efficacy is maintained in the presence of human saliva.

Conclusions. Together these data suggest cetylpyridinium chloride-based mouthwashes are effective at inactivating SARS-CoV-2 variants. This indicates potential to reduce viral load in the oral cavity and mitigate transmission via salivary aerosols.

A Pair of "ACEs"

The emergence of the COVID-19 viral pandemic has generated a renewed interest in pharmacologic agents that target the renin angiotensin system (RAS). Angiotensin-converting enzyme 1 (ACE1) inhibitors decrease the synthesis of angiotensin II (Ang II) from its precursor angiotensin I and inhibit the breakdown of bradykinin, while Ang II receptor blockers antagonize the action of Ang II at the receptor level downstream. The actions of both classes of drugs lead to vasodilation, a blunting of sympathetic drive and a reduction in aldosterone release, all beneficial effects in hypertension and congestive heart failure. ACE2 cleaves the vasoconstrictor Ang II to produce the anti-inflammatory cytoprotective angiotensin 1-7 (Ang 1-7) peptide, which functions through the G protein-coupled receptor MAS to counteract the pathophysiologic effects induced by Ang II via its receptors, including vasoconstriction, inflammation, hypercoagulation, and fibrosis. SARS-CoV-2 enters human cells by binding ACE2 on the cell surface, decreases ACE2 activity, competes for ACE2 receptor-binding sites, and shifts the RAS toward an overexpression of Ang II, accounting for many of the deleterious effects of the virus. Thus, there is great interest in developing recombinant ACE2 as a therapeutic for prevention or treatment of COVID-19. Notably, ACE2 is highly expressed in the oral cavity, and saliva and dorsum of the tongue are major reservoirs of SARS-CoV-2. Cost-effective methods to debulk the virus in the oral cavity may aid in the prevention of viral spread. Here we review the pharmacology of targeted small molecule inhibitors of the RAS and discuss novel approaches to employing ACE2 as a therapeutic for COVID-19.

Provision of Endodontic Treatment in Dentistry amid COVID-19: A Systematic Review and Clinical Recommendations

Background

The risk of acquiring COVID-19 during a pandemic is a major concern among health care workers. Dental professionals being in close proximity to the patients had been exposed more than other health care workers. Hence, all the standard operating procedures (SOPs) are strictly advised to be followed.

Methods

A detailed relevant literature search was conducted in international databases such as PubMed, Web of Science, and Science Direct, from January 2020 to November 2020. All the studies that provided recommendations regarding endodontic procedures during the COVID-19 pandemic were included, and those that were not in the English language, case reports, book chapters, and short communications were excluded in this review. In the end, only 6 articles were selected for the systematic review considering that complete information regarding the provision of dental care in the time of COVID-19 with diagnostic accuracy (STARD) was provided.

Results

Endodontic treatments were restricted to only emergency dental procedures, and all other patients have advised medications and catered through teledentistry. Endodontic emergencies were advised to be carried out with minimal aerosol production procedures.

Conclusion

Provision of endodontic care during COVID-19 restricted to only emergency dental procedures by strictly following standard operating procedures. A protocol for COVID-19 prevention was followed by all the dentists and the dental staff in the dental clinics.

A Sensitive, Portable Microfluidic Device for SARS-CoV-2 Detection from Self-Collected Saliva

Since the outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic in December 2019, the spread of SARS-CoV2 infection has been escalating rapidly around the world. In order to provide more timely access to medical intervention, including diagnostic tests and medical treatment, the FDA authorized multiple test protocols for diagnostic tests from nasopharyngeal swab, saliva, urine, bronchoalveolar lavage and fecal samples. The traditional diagnostic tests for this novel coronavirus 2019 require standard processes of viral RNA isolation, reverse transcription of RNA to cDNA, then real-time quantitative PCR with the RNA templates extracted from the patient samples. Recently, many reports have demonstrated a direct detection of SARS-Co-V2 genomic material from saliva samples without any RNA isolation step. To make the rapid detection of SARS-Co-V2 infection more accessible, a point-of-care type device was developed for SARS-CoV-2 detection. Herein, we report a portable microfluidic-based integrated detection-analysis system for SARS-CoV-2 nucleic acids detection directly from saliva samples. The saliva cartridge is self-contained and capable of microfluidic evaluation of saliva, from heating, mixing with the primers to multiplex real-time quantitative polymerase chain reaction, detecting SARS-CoV-2 with different primer sets and internal control. The approach has a detection sensitivity of 1000 copies/mL of SARS-CoV-2 RNA or virus, with consistency and automation, from saliva sample-in to result-out.

How can biophotonics help dentistry to avoid or minimize cross infection by SARS-CoV-2?

Biophotonics is defined as the combination of biology and photonics (the physical science of the light). It is a general term for all techniques that deal with the interaction between biological tissues/cells and photons (light). Biophotonics offers a great variety of techniques that can facilitate the early detection of diseases and promote innovative theragnostic approaches. As the COVID-19 infection can be transmitted due to the face-to-face communication, droplets and aerosol inhalation and the exposure to saliva, blood, and other body fluids, as well as the handling of sharp instruments, dental practices are at increased risk of infection. In this paper, a literature review was performed to explore the application of Biophotonics approaches in Dentistry focusing on the COVID-19 pandemic and how they can contribute to avoid or minimize the risks of infection in a dental setting. For this, search-related papers were retrieved from PubMED, Scielo, Google Schoolar, and American Dental Association and Centers for Disease Control and Prevention databases. The body of evidence currently available showed that Biophotonics approaches can reduce microorganism load, decontaminate surfaces, air, tissues, and minimize the generation of aerosol and virus spreading by minimally invasive, time-saving, and alternative techniques in general. However, each clinical situation must be individually evaluated regarding the benefits and drawbacks of these approaches, but always pursuing less-invasive and less aerosol-generating procedures, especially during the COVID-19 pandemic.