Efficacy of mouthwash on reducing salivary SARS-CoV-2 viral load and clinical symptoms: a systematic review and meta-analysis

Abstract

Background COVID-19 has been a public health emergency of international concern (PHEIC) for a lengthy period of time. The novel coronavirus is primarily spread via aerosols at a short distance, with infected individuals releasing large amounts of aerosols when speaking and coughing. However, there is an open question regarding whether mouthwash could effectively reduce virus transmission during the COVID-19 pandemic and support the prevention of infection among medical workers. Methods Cochrane Library, PubMed, Web of Science, and Embase databases were systematically searched from the inception of each database to January 12, 2023 for currently available randomized clinical trials (RCTs) on the effect of mouthwash on novel coronavirus load in the oral cavity in COVID-19 patients. The treatment group received mouthwash for rinsing the mouth, while the control group received a placebo or distilled water for COVID-19 patients. The primary outcomes were CT value and viral load. Odds ratios (ORs) were estimated using a random-effects model. Subgroup and sensitivity analyses were performed to minimize the bias and the impact of heterogeneity. Results Thirteen RCTs were included. Seven studies reported the intervention effect of mouthwash on the CT value of novel coronavirus. The analysis results showed that the mouthwash group had a positive impact on the CT value of novel coronavirus [ SMD = 0.35, 95% CI (0.21, 0.50)] compared with the control group. In addition, subgroup analysis showed a significant positive effect of mouthwash on CT values in the treatment group compared with the control group, with chlorhexidine (CHX) [SMD = 0.33, 95% CI (0.10, 0.56)], povidone-iodine (PVP-I) [SMD = 0.61, 95% CI (0.23, 0.99)], or hydrogen peroxide (HP) [SMD = 1.04, 95% CI (0.30, 1.78)] as an ingredient of the mouthwash. Six studies reported the intervention effect of mouthwash on the viral load, 263 cases in the treatment group and 164 cases in the control group. The analysis results showed that there was no statistical difference between the mouthwash group and the control group in the viral load of novel coronavirus [SMD = -0.06, 95% CI (-0.18, 0.05)]. In the subgroup analysis by measurement time, there were statistically significant differences between the mouthwash and control groups for CT values [SMD = 0.52, 95% CI (0.31, 0.72)] and viral load [SMD = − 0.32, 95% CI (− 0.56, − 0.07)] within 30 min of gargling. Conclusions In summary, mouthwash has some efficacy in reducing the viral load of novel coronavirus, especially within 30 min after rinsing the mouth. Mouthwash containing CHX, PVP-I and HP all had significant positive effects on CT values, and PVP-I-containing mouthwash may be a promising option to control novel coronavirus infections and relieve virus-related symptoms. However, studies on the dose and frequency of use of mouthwash for infection control are still lacking, which may limit the clinical application of mouthwash. Trial registration Protocol registration: The protocol was registered at PROSPERO (CRD42023401961).

Oral mouthwashes for asymptomatic to mildly symptomatic adults with COVID-19 and salivary viral load: a randomized, placebo-controlled, open-label clinical trial

“…A recent randomized, double-blind, controlled clinical trial has also indicated that SARS-CoV-2 RNA copy numbers were stable for up to 60 min after the use of 0.05% CPC mouthwash [ 16 ]. Recent systematic reviews have also shown that using 0.075% CPC-containing mouthwashes may not be effective in reducing SARS-CoV-2 viral load [ 40 , 41 ]. This might be due to the fact that the antiviral effects of CPC against SARS-CoV-2 are the result of lipid membrane disruption in the viral envelope, without an effect on viral RNA integrity [ 42 – 44 ].…”

Eligibility and efficacy of a CPC‐ and CHX‐based antiviral mouthwash for the elimination of SARS‐CoV‐2 from the saliva: A randomized, double‐blind, controlled clinical trial

“…A recent systematic review and meta-analysis reported a positive impact of mouthwashes on SARS-CoV-2 Ct values compared with the control group, especially within 30 min of rinsing. However, none of the included studies explored the impact of CPC-CHX on SARS-CoV-2 viral load (Zhang et al, 2023).…”