Changes in reverse transcription polymerase chain reaction cycle threshold values of SARS-CoV-2 with topical povidone iodine use: A single-arm open-label interventional study.

Context: Repurposed povidone iodine (PVP-I) has been suggested as an effective adjuvant against coronavirus disease-2019 (COVID-19).

Aim: The aim of this study was to assess the changes in RT-PCR cycle threshold (Ct) values of severe acute respiratory Syndrome Coronavirus-2 (SARS-CoV-2) genes with PVP-I intranasal and oral application.

Settings And Design: A longitudinal (repeated measures) single-arm open-label interventional study was conducted for 200 samples of ten COVID-19 patients in South India.

Methods And Material: Demographic and clinical information were collected. Intranasal application and oral gargle with 1% PVP-I solution was done four times a day for seven days. Nasopharyngeal and oropharyngeal samples were taken for RT-PCR test at hour-0, hour-2, hour-4 on Day-0, Day-3, Day-6, and hour-0 on Day-9.

Methods And Material: STATA analysis software version 14.2 was used. McNemar Test was applied for paired samples. Skilling Mack Test was used to assess the association between PVP-I use (intra-day and inter-day) and / Ct values. Pearson correlation coefficients and Bland-Altman plots were used for further analyses.

Results: Mean (SD) age of the patients was 41.5 (±8.82) years. A total of 100 pairs of nasopharyngeal and oropharyngeal samples were analysed. No significant difference was observed in the Ct values of asymptomatic and symptomatic patients. Ct values (nasopharyngeal) at Hour-0 increased from Day-0 to Day-9 ( = 0.005). Ct value was higher at Hour-2 for most of the samples.

Conclusions: RT-PCR results (qualitative) differed at various testing points in the same patients. Lower Ct values were found in the nasopharyngeal samples. Successive increase in Ct values indicates reduced viral load with natural course of COVID-19. PVP-I may have an optimal impact within 2 h of usage.

Clinical Trial Registration Number: CTRI/2020/05/024962.