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

Infection. 2021 Apr;49(2):305-311. doi: 10.1007/s15010-020-01563-9. Epub 2020 Dec 14.


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.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Anti-Infective Agents, Local / therapeutic use*
  • COVID-19 / prevention & control
  • COVID-19 / transmission
  • COVID-19 / virology
  • COVID-19 Drug Treatment*
  • Cetylpyridinium / analysis
  • Cetylpyridinium / therapeutic use
  • Chlorhexidine / analogs & derivatives
  • Chlorhexidine / analysis
  • Chlorhexidine / therapeutic use
  • Female
  • Humans
  • Male
  • Middle Aged
  • Mouthwashes / chemistry
  • Mouthwashes / therapeutic use*
  • Povidone-Iodine / analysis
  • Povidone-Iodine / therapeutic use
  • SARS-CoV-2 / drug effects*
  • Saliva / virology*
  • Singapore
  • Treatment Outcome
  • Viral Load / drug effects*
  • Young Adult


  • Anti-Infective Agents, Local
  • Mouthwashes
  • Povidone-Iodine
  • Cetylpyridinium
  • chlorhexidine gluconate
  • Chlorhexidine