Discussion
infection, critically ill, illness, respiratory and cardiovascular disease
VIRUS, CRITICALLY ILL, DISEASE, INFECTION, OF DISEASE TRANSMISSION, CORONAVIRUS, ORAL INFECTION
This pilot study provided important information on the impact of three different mouthwashes containing 0.2% Chlorhexidine digluconate (CHX), 1.5% Hydroxide peroxide (HTo the best of authors’ knowledge this is the first clinical study to investigate the efficacy of different mouthwashes in reducing viral load in the saliva of COVID-19 patients with delta variant. Among the participants included in the present investigation, delta SARS-CoV-2 strain was the most prevalent whilst in other clinical studies the type of SARS-CoV-2 strain investigated was not disclosed. Previous studies have found that lower concentrations of CPC (10–40 μg/mL) presented anti-SARS-CoV-2 effects in many strains (Wuhan, Alpha, Beta, and Gamma). Meister et al.In the present study, SARS-CoV-2 viral load was assessed by RT-qPCR and was normalized to two reference genes; one external rat gene and another a human actin gene to consider extraction variation in human material. In previous studiesThe variability in the viral load, also observed in the control group of the present investigation, may be explained by naturally occurring changes in the shedding of viruses from other body niches like the nasopharynx. This information can be supported by the fact that persistent viral genetic material has been identified in upper respiratory samples weeks after the COVID-19 symptoms have disappeared. SARS-CoV-2 replicates abundantly in upper respiratory epithelia, where ACE2 is expressedDespite the mouthwashes used in the current study did not contain ethanol on their formulation, other commercially available mouthwashes can also be formulated with ethanol which could have contributed for reducing viral load. However, the majority of evidence available on the efficacy of mouthwashes in reducing viral load did not provide detailed information on the formulation of the mouth rinses investigated. In a study by Biber et al.SARS-CoV-2 viral RNA was detected in the saliva samples from 85% (45/53) of our patients diagnosed with COVID-19. On average, the mean time from the onset of symptoms to the study visit and saliva sample collection was around 8 days (ranging from 3 -18 days). The median incubation period from infection with SARS-CoV-2 to onset of symptoms is approximately 5 days with viral load reduction with recovery. Despite that, hospitalised individuals presenting with more severe illness are more likely to exhibit longer shedding of potentially infectious virus. Although the number of days from onset of symptom could have influenced the salivary viral load of the patients initially consented in this study, viral RNA was still detected in most of the saliva samples. Similarly, to the present investigation, previous studies were able to identify SARS-CoV-2 in 83.6–91.7% of the saliva samples obtained from COVID-19 positive patientsThe results from the present study should be considered in the context of some limitations. This study included critically ill hospitalized COVID-19 patients. Although participants were instructed and refrained from eating, drinking, or performing oral hygiene for at least 30 min prior each saliva sample collection, it was challenging to control and restrict the intake of drinks and food during the whole period of the study visit. In addition, most patients were on oxygen via nasal cannula which may have contributed to the reduction of the salivary flow. The authors also acknowledge that the inclusion of an additional group, who would rinse their mouth with saline or distilled water, would have allowed for a better understanding of the mechanical effect of rinsing on the outcomes. However, including the comparison of mouthwash use to not rinsing the mouth at all was deemed important to gather information on the saliva viral load specifically for those patients who did not perform any oral hygiene procedures. Furthermore, although in the present study patients taking antivirals or drugs that could have influenced salivary viral load were not excluded, the number of subjects taking medications were evenly distributed among groups and were unlikely to influence main results.Despite the current findings, the direct potential benefit of reducing SARS-CoV-2 load in the saliva of COVID-19 positive patient, in terms of disease transmission and patient wellbeing, is still unknown and needs to be further investigated. In future studies, the use of different or novel antimicrobial oral solutions could be established as a possible approach to either reduce transmission of coronavirus in the early stages of infection, especially among health professional (i.e., dentists, surgeons, and anaesthetists) or reduce viral load to potentially restrict virus transmission preventing future disease outbreaks. Additionally, it is not known if the reduction of salivary viral load could contribute to alleviate patients’ symptoms. Irrespective of its effect on SARS-CoV-2 salivary load, it is important to note the significance of maintaining good oral hygiene and care for patients diagnosed or suspected to have COVID-19 during and after infection resolves. Previous studies have demonstrated the importance of oral hygiene in overall health, particularly in hospitalized patients, and its association with various systemic conditions including respiratory and cardiovascular disease. Good oral hygiene practices, such as regular brushing, interdental cleaning, and mouthwash use, can contribute to maintain oral health and prevent oral infections, which can impact individuals overall well-being.