Povidone-Iodine safe and effective option for eradicating COVID-19 from Sinonasal and Oral Cavities: Study

Particular concern has been expressed regarding the safety of otolaryngologists, patients, and staff during routine and endoscopic examination. Reports have demonstrated high viral loads of SARS-CoV-2 in the nasal cavities, nasopharynx, oral cavities, and oropharynx, with the highest viral loads within the nasopharynx. Due to high viral load, these areas are sensitive for diagnosis of the virus. The transit of virus via coughing, sneezing, and aerosolizing procedures makes transmission high. Aerosols of SARSCoV-2 have been detected in the air for up to 3 hours.

Transmission reduction by the minimization of aerosolized virus is of key importance. Given that the nasopharynx and oropharynx are principal reservoirs of active SARS-CoV-2 virus, there has been immense desire for an approach to nasal and oral decontamination in the era of COVID-19. Povidoneiodine (PVP-I) has been suggested as a topical solution. PVP-I works by releasing free iodine, which disrupts microbial metabolic pathways, destabilizes structural components of cell membranes, and leads to irreversible damage to pathogens. It is a potent virucidal via inhibition of N1, N2, and N3 neuraminidase as well as inhibition of hemagglutinin. This inhibition blocks viral attachment to cellular receptors and inhibits viral release and spread from infected cells.

Frank et al carried out a study with an objective to present established uses of PVP-I in the sinonasal and oral cavities and outline the safety profile through the discussion of clinical and in vitro toxicity. In addition, they aimed to discuss PVP-I efficacy against coronaviruses and its potential use specifically against SARS-CoV-2 to inform the otolaryngology community regarding its use.

A review was performed utilizing PubMed and Cochrane Databases. Search terms included ''sinonasal povidone-iodine,'' ''nasal povidone-iodine,'' ''oral povidone-iodine,'' and ''povidone-iodine safety.'' All citations in published protocols for nasal and oral PVP-I use regarding COVID-19 were independently reviewed.

Povidone-iodine had been safely administered for up to 5 months in the nasal cavity and 6 months in the oral cavity. Concentrations less than 2.5% in vitro do not reduce ciliary beat frequency or cause pathological changes in ciliated nasal epithelium, upper respiratory, or mucosal cells. Adverse events with oral use have not been reported in conscious adults or children. Allergy and contact sensitivity is rare. Chronic mucosal use up to 5% has not been shown to result in clinical thyroid disease. PVP-I is rapidly virucidal and inactivates coronaviruses, including SARS-CoV and Middle East Respiratory Syndrome (MERS).

The SARS-CoV-2 pandemic has altered the environment in which we practice medicine. Attempts to minimize spread have mainly concentrated on strict adherence to the use of physical barriers, spatial separation, and personal protective equipment. The nasal cavities, nasopharynx, oral cavity, and oropharynx have high viral loads of SARS-CoV-2. There is a growing interest for decontamination of these areas in patients and health care workers to prevent virus transmission. PVP-I is of primary interest due to its ability to inactivate coronaviruses, the lack of microbial resistance, and the long history of clinical use.

Povidone-iodine is safe in the nose up to 1.25% and mouth up to 5% for up to 5 and 6 months, respectively. Absorption of iodine is poorly described, inconsistently analyzed, and without clear conclusions. Regardless, PVP-I has been demonstrated to be systemically risk free at concentrations up to 5% daily for 5 months.

The authors recommend nasal mucosal decontamination with 0.5 to 2 mL of 1.25% PVP-I and oral rinse with up to 10 mL at 2.5% as frequently as needed for decontamination without risk of adverse effects. Povidone-iodine nasal and oral use should be avoided in patients with thyroid disease, pregnant patients, and patients receiving radioactive iodine therapy. If PVP-I is to be used in unconscious patients, care must be taken by using small amounts via direct application to mucosal surfaces to avoid the risk of aspiration. Povidone-iodine is effective against SARS-CoV and MERS at 0.23% after 15 seconds of exposure in vitro. Based on homology demonstrated between SARS-CoV and SARSCoV-2, it is likely that PVP-I is effective in safely eradicating SARS-CoV-2 in the nasal cavity, nasopharynx, oral cavity, and oropharynx. However, there are no existing data evaluating the efficacy of PVP-I on SARS-CoV-2. Studies are needed to characterize the utility of PVP-I against this new pathogen.

Source: Frank et al; Ear, Nose & Throat Journal

DOI: 10.1177/0145561320932318