Povidone-iodine nasal antiseptic completely inactivates SARS-CoV-2 in 15 secs

Povidone-iodine nasal antiseptic solutions completely inactivate SARS-CoV-2 virus at concentration as low as 0.5% in just 15 seconds, an in vitro study shows.

“[As the nasal mucosal] represents the dominant initial site for infection … transnasal viral inactivation may not only prevent person-to-person spread of SARS-CoV-2, but may also diminish the severity of disease in patients by limiting spread and decreasing viral load delivered to the lungs,” explained the researchers.

“[Hence,] povidone-iodine nasal irrigation … may play an adjunctive role in mitigating viral transmission beyond personal protective equipment [such as mask],” they suggested.

Povidone-iodine nasal antiseptics were tested at three concentrations (0.5%, 1.25%, and 2.5%) on efficacy of SARS-CoV-2 inactivation. Reduction in log value of more than three log₁₀ of the 50 percent cell culture infectious dose of the virus was considered complete inactivation. [JAMA Otolaryngol Head Neck Surg 2020;doi10.1001/jamaoto.2020.3053]

All three concentrations of povidone-iodine nasal antiseptics led to complete inactivation of the virus within 15 seconds.

In contrast, ethanol 70% solution which was used as a positive control did not achieve complete viral inactivation after 15 seconds. It did, however, inactivated the virus completely after 30 seconds.

“At a contact time of 15 seconds … the nasal antiseptics tested performed better than the standard positive control routinely used for in vitro assessment of anti–SARS-CoV-2 agents,” observed the researchers.

There were no cytotoxic effects on cells seen with any of the compounds tested.

While a previous in vitro study has shown that povidone-iodine solutions have inhibitory effects on ciliary beat frequency (CBF) of mucociliary cells in a concentration-dependent manner, experimental models demonstrated that solutions up to 1.25% did not have such inhibitory effects and might be tolerated for short-term use in the nasal epithelium.

As such, the authors have implemented the use of povidone-iodine nasal antiseptics in their practice. “We have updated all of our protocols to include use of 1.25% aqueous povidone-iodine formulations delivered to each nasal cavity in patients before any intranasal procedure.”

Implementing use of intranasal povidone-iodine antiseptics in patients prior to intranasal procedures can help reduce viral spread via droplet and aerosol, they pointed out.  

“Healthcare professionals may consider instructing patients to perform nasal decontamination with povidone-iodine prior to presenting for their procedure … [and] additionally be considered for use by healthcare professionals for prophylaxis,” suggested the researchers.

“Nevertheless, thyroid function testing should be considered when povidone-iodine is regularly administered to patients for more than 3 months,” they cautioned. “[In addition,] use of intranasal povidone-iodine is contraindicated in patients with an allergy to iodine, patients who are pregnant, patients with active thyroid disease, and patients undergoing radioactive iodine therapy.”