Efficacy of commercial mouth-rinses on SARS-CoV-2 viral load in saliva: randomized control trial in Singapore

Abstract

Purpose: One of the key approaches to minimize the risk of COVID-19 transmission would be to reduce the titres of SARS-CoV-2 in the saliva of infected COVID-19 patients. This is particularly important in high-risk procedures like dental treatment. The present randomized control trial evaluated the efficacy of three commercial mouth-rinse viz. povidone-iodine (PI), chlorhexidine gluconate (CHX) and cetylpyridinium chloride (CPC), in reducing the salivary SARS-CoV-2 viral load in COVID-19 patients compared with water.

Methods: A total of 36 SARS-CoV-2-positive patients were recruited, of which 16 patients were randomly assigned to four groups-PI group (n = 4), CHX group (n = 6), CPC group (n = 4) and water as control group (n = 2). Saliva samples were collected from all patients at baseline and at 5 min, 3 h and 6 h post-application of mouth-rinses/water. The samples were subjected to SARS-CoV-2 RT-PCR analysis.

Results: Comparison of salivary Ct values of patients within each group of PI, CHX, CPC and water at 5 min, 3 h and 6 h time points did not show any significant differences. However, when the Ct value fold change of each of the mouth-rinse group patients were compared with the fold change of water group patients at the respective time points, a significant increase was observed in the CPC group patients at 5 min and 6 h and in the PI group patients at 6 h.

Conclusion: The effect of decreasing salivary load with CPC and PI mouth-rinsing was observed to be sustained at 6 h time point. Within the limitation of the current study, as number of the samples analyzed, the use of CPC and PI formulated that commercial mouth-rinses may be useful as a pre-procedural rinse to help reduce the transmission of COVID-19. ISRCTN (ISRCTN95933274), 09/09/20, retrospectively registered.

Keywords: Antiseptics; COVID-19; Clinical trial; Mouth-rinses; SARS-CoV-2; Saliva.

Fig. 1

Cycle threshold (Ct) profile in saliva of SARS-CoV-2-positive patients treated with mouth-rinses. Dots represent Ct value for each patient. Horizontal bar represents the mean value and vertical bar represents the 95% confidence interval

Fig. 2

Relative fold change of Cycle threshold (Ct) values in mouth-rinse and water group patients. The column size represents the mean of fold change of Ct value at each time point with respect to its baseline Ct value and the bars represents the standard deviation. Each mouth-rinse group patients—povidone–iodine (PI), chlorhexidine gluconate (CHX) and Cetylpyridinium chloride (CPC) were compared with water group patients using Independent t test. **Represents p < 0.01 and *represents p < 0.05.