A prospective, randomized, open-label trial of early versus late povidone-iodine gargling in patients with COVID-19

Povidone-iodine (PVP–I) is a broad-spectrum antiseptic reagent that has been used for over 50 years. The purpose of this study is to look into the effect of gargling with PVP–I gargling on virus clearance and saliva infectivity in COVID-19. A prospective, randomized, open-label trial of intervention with PVP–I was conducted at three quarantine facilities in Osaka, Japan, enrolling adolescents and adults with asymptomatic-to-mild COVID-19. Patients were randomly allocated to the early and late intervention group at a 1:1 ratio. The early group gargled with PVP–I from days 2 to day 6; the late group gargled with water first, then with PVP–I from day 5 after sampling till day 6. The primary and secondary endpoints were viral clearance for SARS-CoV-2 using RT-qPCR at days 5 and 6, respectively, and the investigational endpoint was saliva infectivity clearance on day5. We enrolled 430 participants, with 215 assigned to each group, and 139 in the early group and 140 in the late had a positive saliva RT-qPCR test on day 2. On day 5, the early group had a significantly higher RT-qPCR negative rate than that of the late group (p = 0.015), and the early had a significantly higher clearance rate of infectivity (p = 0.025). During the PVP–I intervention, one participant reported oropharyngeal discomfort. Gargling with PVP–I may hasten virus clearance and reduce viral transmission via salivary droplets and aerosols in patients with asymptomatic-to-mild COVID-19. (Clinical trial registration numbers: jRCT1051200078 and dateof registration: 24/11/2020).