Evaluation of Slow-release Mucoadhesive Paste of” MUCODENTOL “in Oral Vestibule on Prophylaxis of Symptoms and Signs of COVID-19 Disease: A triple-blind, randomized clinical trials

Technical Summary: Evaluation of Slow-release Mucoadhesive Paste of "MUCODENTOL" in Oral Vestibule on Prophylaxis of Symptoms and Signs of COVID-19 Disease

Problem Statement
The study addresses the critical need for effective prophylactic measures against SARS-CoV-2, particularly for high-risk healthcare workers (HCWs) in Iran, where the disease caused significant morbidity and mortality. While standard protocols (PPE, hand hygiene) are essential, the authors posit that the oral cavity serves as a primary site for initial viral colonization due to the abundance of ACE2 receptors. The research investigates whether a topical intervention targeting the oral vestibule can reduce the local viral load, thereby preventing the onset or mitigating the severity of COVID-19 symptoms in asymptomatic personnel exposed to the virus. The specific intervention is "Mucodentol," a slow-release mucoadhesive paste containing 3% Carvacrol, a phenolic compound with documented antimicrobial and antiviral properties.

Methodology
The research was conducted as a triple-blind, randomized, placebo-controlled field trial involving 1,624 asymptomatic healthcare workers across multiple hospitals in Lorestan and Qom provinces during the first quarter of 2020.

• Study Design & Randomization: Participants were stratified by city, gender, and age group, then assigned via permuted block randomization to either the Mucodentol group or an identical placebo group. The study was triple-blinded, ensuring that participants, outcome assessors (non-research team members), and data analysts were unaware of the group assignments.
• Intervention: The intervention group applied two drops of Mucodentol paste into the buccal vestibule three times daily and before sleep for four weeks. The placebo group received an identical-appearing paste. Both groups received standard Ministry of Health PPE protocols.
• Data Collection: Symptom severity was assessed weekly via telephone interviews using a researcher-developed checklist covering seven primary symptoms (fever, dry cough, shortness of breath, loss of taste/smell, sore throat, myalgia, arthralgia) and secondary outcomes.
• Statistical Analysis: Data were analyzed using an Intention-to-Treat (ITT) approach with missing data handled via Last Value Carried Forward. The primary analysis utilized Generalized Estimating Equations (GEE) with an identity link and exchangeable correlation structure to model the effect of the intervention on symptom severity scores over time, adjusting for confounders such as hospital of service, job category, gender, underlying diseases, and tobacco use.

Key Results
The analysis revealed a statistically significant group-by-time interaction for the total symptom severity score ($p < 0.001$), indicating that the efficacy of Mucodentol evolved dynamically over the four-week period.

• Symptom-Specific Efficacy:
  • Increasing Benefit: Several symptoms showed a therapeutic effect that increased over time, including dry cough, fatigue, myalgia, and arthralgia.
  • Time-Dependent Variation: The effect on sore throat and chills was most pronounced in the early weeks (Time 1 and 2), while the effect on fever decreased over time.
  • Consistent Main Effects: For symptoms without a significant time interaction, Mucodentol still demonstrated a significant overall reduction in severity compared to placebo, specifically for shortness of breath ($p=0.004$), fatigue ($p<0.001$), and diarrhea ($p<0.001$).
  • Neurological/Sensory: Significant benefits were observed for ageusia (loss of taste) and anosmia (loss of smell), with the largest effects noted at Time 2.
• Non-Significant Findings: No significant main effects or time interactions were found for hemoptysis, nausea, vomiting, or anorexia, though these symptoms showed temporal variation across the study period. Headache showed a non-significant trend toward benefit ($p=0.058$).

Key Contributions

1. Clinical Evidence for Topical Prophylaxis: The study provides clinical data suggesting that a mucoadhesive paste containing Carvacrol can significantly reduce the severity of COVID-19 symptoms in high-risk populations, supporting the hypothesis that reducing oral viral load is a viable prophylactic strategy.
2. Formulation Innovation: It highlights the utility of a slow-release mucoadhesive delivery system for antiviral agents. The authors argue that this formulation ensures prolonged mucosal contact and sustained release of Carvacrol, potentially offering a cumulative protective effect that standard rinses or sprays may not achieve.
3. Mechanistic Validation: The results align with existing in vitro literature regarding Carvacrol's ability to disrupt viral envelopes and its anti-inflammatory properties (inhibiting COX-2 and prostaglandin biosynthesis), suggesting a dual mechanism of action: direct viral inactivation and attenuation of mucosal inflammation.

Significance and Claims
The paper claims that Mucodentol offers a significant and progressively evolving benefit in reducing the overall clinical severity of COVID-19 among healthcare workers. The authors position the product as a safe, innovative, and suitable adjunct for continuous use in high-exposure environments, particularly where standard PPE may be insufficient or as a complementary layer of protection.

The study emphasizes that while the intervention did not eliminate symptoms entirely, the reduction in severity scores across multiple systemic and respiratory manifestations is clinically meaningful. The authors conclude that the findings support the World Health Organization's recommendation of phenolic compounds as virucidal agents. However, the paper maintains a modest tone regarding its limitations, acknowledging the inability to perform baseline PCR for all participants, potential adherence issues, and the evolving nature of diagnostic criteria during the early pandemic. Consequently, the authors call for further multicenter trials with molecular confirmation (PCR/antigen) and extended follow-up to validate long-term efficacy and safety against emerging variants.