Povidone-iodine (PVP-I) is a well-tried antiseptic agent with excellent virucidal (99.99%) properties. However, repurposing it against coronavirus disease-19 (COVID-19) has been lesser tested in vivo. Severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) enters frequently by the nasopharynx, thus preventing colonization of the virus could help to reduce the incidence of infection. 

PVP-I gargle and mouthwash have been demonstrated to be effective in rapidly inactivating SARS-CoV-2 in vitro on a smaller scale (Hassandarvish et al. in BDJ 1-4, 2020, Pelletier et al. in ENTJ 1-5, 2020). However, its efficacy in humans is lacking. 

The present study assessed the virucidal effect of PVP-I against SARS-CoV-2 located in the nasopharynx of RT-PCR-confirmed COVID-19 cases aged 18 years and above with symptoms. single time application of PVP-I nasal irrigation (NI) at diluted concentrations of 0.4%,0.5% and 0.6% and PVP-I nasal spray (NS) at diluted concentrations of .5% and .6% was done and nasopharyngeal clearance of SARS-CoV-2 was tested and compared to the corresponding controls (distilled water). 

Viral clearance in a repeat RT-PCR (qualitative) and the number of adverse events were evaluated. 

189 confirmed COVID-19 cases were enrolled and randomized into seven groups, with each group containing 27 patients. Of all, 84.1% were male, and 15.9% were female. a substantial proportion of nasopharyngeal clearance with all strengths of PVP-I NI and PVP-I NS was seen compared to the corresponding controls. Further, 0.5% NI was found to be significantly better than 0.5% NS for viral clearance and had the highest nasopharyngeal clearance among all strengths. 0.6% NS was found to be superior to CNS and 0.5% NS in viral clearance. The only adverse event recorded was nasal irritation in two patients each in the 0.4% and 0.6% PVP-I NI groups. 

Thus, PVP-I NI and NS proved to be an effective virucidal agents against SARS-CoV-2 in the human body. The authors recommended using PVP-I in the nasopharynx (as well as oropharynx) to prevent COVID-19.

Source- Indian J Otolaryngol Head Neck Surg. 2021 May, 18:1-5. doi: 10.1007/s12070-021-02616-7. Epub ahead of print. PMID: 34026595; PMCID: PMC8130786.