A Cetylpyridinium Chloride Oral Rinse Reduces Salivary Viral Load in Randomized Controlled Trials

Introduction: Evaluating the antiviral potential of commercially available mouthrinses on SARS-CoV-2 holds potential for reducing transmission, particularly as novel variants emerge. Because SARS-CoV-2 is transmitted primarily through salivary and respiratory secretions and aerosols, strategies to reduce salivary viral burden in an antigen-agnostic manner are attractive for mitigating spread in dental, otolaryngology, and orofacial surgery clinics where patients may need to unmask.

Methods: Patients (n = 128) with confirmed COVID-19-positive status within 10 days of symptom onset or positive test result were enrolled in a double-blind randomized controlled trial of Food and Drug Administration-approved mouthrinses containing active ingredients ethanol, hydrogen peroxide, povidone iodine, chlorhexidine gluconate, cetylpyridinium chloride (CPC), or saline. The CPC, ethanol, and sterile water rinses were followed in a second double-blind randomized controlled trial (n = 230). Participants provided a saliva sample before rinsing (baseline) and again at 30 and 60 min after rinse. Quantitative polymerase chain reaction was used to determine salivary SARS-CoV-2 viral load at all time points. An adjusted linear mixed-effect model was employed to compare viral load after rinsing relative to baseline.

Results: The rinse containing CPC significantly reduced salivary SARS-CoV-2 viral load 30 min postrinse relative to baseline (P = .015), whereas no other rinse significantly affected viral load at 30 min after rinsing. At 60 min postrinsing, no group had a significant reduction in SARS-CoV-2 copy number relative to baseline, indicating a rebound in salivary viral load over a 1-hour window. Participants indicated a fair to good rinsing experience with the CPC product and high willingness to use oral rinses before and during dental and medical health care visits.

Conclusions: Our findings suggest that preprocedural oral rinsing could be implemented as a feasible, inexpensive approach to mitigate spread of SARS-CoV-2 and potentially other enveloped viruses for short periods, which is relevant to clinical procedures involving the nasal and oropharyngeal region.

Knowledge transfer statement: Rinsing with a cetylpyridinium chloride-containing mouthrinse can significantly reduce salivary SARS-CoV-2 viral load for up to 30 min; patients are willing to use mouthrinses in medical and dental settings to limit transmission risk in clinics.