Povidone-Iodine Nasal Spray Does Not Demonstrate Virucidal Activity in COVID-19–Positive Patients

by Linda Kossoff •

What is the effect of povidone-iodine (PVP-I) nasal sprays on nasopharyngeal (NP) viral load as assessed by cycle threshold (Ct) on quantitative polymerase chain reaction (qPCR) of SARSCoV-2 in outpatients?

BOTTOM LINE

Dilute versions of PVP-I nasal spray appear safe for topical use in the nasal cavity, but PVP-I does not demonstrate virucidal activity in COVID-19–positive patients.

BACKGROUND: Studies demonstrate a correlation between SARS-CoV-2 viral load and COVID-19 severity, mortality, and infectivity. SARS-CoV-2 transmission occurs primarily through the spread of aerosolized droplets into the nose. Therefore, direct application of a topical virucidal treatment, such as PVPI, to nasopharyngeal tissues would be expected to decrease viral burden in exposed patients.

STUDY DESIGN: Prospective randomized control trial.

SETTING: Department of Otolaryngology–Head and Neck Surgery, Stanford University School of Medicine, Stanford, Calif.

SYNOPSIS: Researchers identified 35 outpatients (51.4% female, mean age 43.2 years) with a positive NP swab for COVID- 19 within five days prior to enrollment. Participants were randomized into three treatment groups: 0.9% NaCl (saline [placebo], n=11), 0.5% PVP-I in water (n=11), and 2% PVP-I in water (n=13). After a baseline NP swab, patients received randomized spray bottles and self-administered two sprays per nostril. Additional swabs were collected one hour post-spray, and nine additional treatments were self-administered (two sprays/nostril, 4X/day). Another swab was collected on day three. Symptoms and adverse event questionnaires were completed at baseline, day three, and day five. University of Pennsylvania Smell Identification Tests were completed at baseline and day 30. Saline and PVP-I groups both had minimal changes in Ct at the one-hour point. Over time, mean Ct values increased in all groups, indicating declining viral loads. There was no statistically significant difference in the rate of changes between placebo and PVP-I groups. All sprays were well tolerated, but the 2.0% PVP-I group reported more nasal burning. Olfaction improved in all groups over 30 days. Study limitations included lack of a negative control group.

CITATION: Zarabanda D, Vukkadala N, Phillips KM, et al. The effect of povidone-iodine nasal spray on nasopharyngeal SARS-CoV-2 viral load: A randomized control trial. Laryngoscope. 2022;132:2089-2095