Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is primarily transmitted through the aerosolization of droplets containing contaminated nasopharyngeal secretions. Povidone Iodine solutions at concentrations as low as 0.5% rapidly inactivate SARS-CoV-2 in vitro with contact times as short as 15 seconds. 

The authors investigated whether the nasopharyngeal application of PI could reduce the viral load of patients with nonsevere coronavirus disease 2019 (COVID-19) symptoms.

The study included adult outpatients (≥18 years old) having tested highly positive (cycle threshold ≤20) for SARS-CoV-2 ribonucleic acid (RNA) by reverse transcription-polymerase chain reaction (RT-PCR) in nasopharyngeal swabs within the previous 48 hours.

Patients underwent an additional nasopharyngeal swab for viral quantification at baseline before being randomly assigned (1:1) to a control group (no intervention, n = 12) or an intervention group (n = 12). The intervention consisted of 4 successive types of mouthwash and gargles with 25 mL of 1% aqueous PI solution, followed by one 2.5-mL nasal pulverization of the same solution into each nostril using an intranasal mucosal atomization device connected to a 5-mL syringe while sniffing and one application on each nasal mucosa of a dab of 10% PI ointment followed by a massage of the nostril to help spread the ointment. Patients were trained during the first decolonization session and received the necessary materials and a guide to help them perform the following sessions four times a day for five days. Follow-up was done on day one and then every two days until day 7 to assess the efficacy (viral quantification) and safety of the decolonization. All nasopharyngeal swabs were taken at least 3 hours after the last PI application to quantify viral RNA using RT-PCR.

The Median (IQR) age of patients in the control group was 57 (45-68) years, and in the intervention group was 33 (23-46) years. The mean relative difference in viral titers between baseline and day 1 was 75% (95% CI, 43%-95%) in the intervention group and 32% (95% CI, 10%-65%) in the control group. 

Nasopharyngeal decolonization may reduce the carriage of infectious SARS-CoV-2 in adults with mild to moderate COVID-19.

Source: JAMA Otolaryngol Head Neck Surg. 2021 Apr 1;147(4):400-401. doi: 10.1001/jamaoto.2020.5490.