Effect of 0.5% povidone-iodine on the nasopharyngeal and oropharyngeal viral loads in patients with COVID-19: A double-blind placebo-controlled randomized clinical trial

Background and Objective: The povidone-iodine (PvP-I) nasal antiseptic has been shown to completely inactivate the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in vitro at variable concentrations. This study was performed to investigate the effect of 0.5% PvP-I nasal drops and oral gargles on the nasopharyngeal and oropharyngeal viral loads in SARS-CoV-2-positive patients. Methods: This was a double-blind, placebo-controlled, randomized clinical trial among patients aged ≥18 years with reverse-transcriptase polymerase chain reaction confirmed in the mild to moderate category of SARS-CoV-2 infection. A total of 32 patients were randomly assigned to receive either freshly prepared 0.5% PvP-I solution or distilled water in the form of supervised self-administered 4-5 nasal drops, followed by 20 ml for gargling for at least 30 seconds. The main outcome measure was the mean change in viral titer and Ct values in the nasopharyngeal and oropharyngeal samples at baseline, 5 minutes, and 3 hours post intervention. Results: The mean change in viral titers across the time duration for the test group when compared with the control group was not statistically significant (P = 0.109). However, the mean change in Ct value was found to be borderline statistically significant (P = 0.042). Noticeable differences were noted among the mean viral titers and Ct values in the intervention group when plotted against the time of testing as compared to the control group. PvP-I solution at 0.5% dilution was well tolerated, and no evident side effects were reported. Conclusions: This study shows that 0.5% PvP-I has an effect on reducing nasopharyngeal and oropharyngeal viral loads in COVID-19 patients. This can be of substantial aid for the primary care physicians, especially for the practitioners in remote and resource poor areas.