Effectiveness of mouth rinses against COVID-19: a systematic review and network meta-analysis

This systematic review and network meta-analysis (NMA) comprehensively compared the effectiveness of different mouth rinses in reducing the viral load/infectivity of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) (Part I), alleviating clinical symptoms or severity of disease (Part II), and decreasing the incidence of SARS-CoV-2 infection (Part III).

Randomized controlled trials (RCTs) and non-randomized controlled trials (NRCTs) with restrictions were searched up to 3^rd March 2023. Twenty-three studies (22 RCTs and one NRCT) met the inclusion criteria for this systematic review.

Five RCTs (454 patients and nine interventions) in Part I were eligible for NMA. The NMA results showed that, in comparison with no rinse, sodium chloride (NaCl) was the most effective mouth rinse for reducing the viral load, followed by povidone-iodine (PVP-I), ß-cyclodextrin + citrox (CDCM), hydrogen peroxide (HP), chlorhexidine gluconate (CHX), cetylpyridinium chloride (CPC), placebo and hypochlorous acid (HClO). However, these results were not significant. Based on surface under the cumulative ranking curve scores, PVP-I was likely to be the most efficacious mouth rinse for reducing SARS-CoV-2 viral load, followed by CDCM, HP, NaCl, CHX, CPC, placebo, no rinse and HClO.

Due to heterogeneity of the primary studies, the effectiveness of different mouth rinses to reduce viral infectivity, improve clinical symptoms or prevent SARS-CoV-2 infection remains inconclusive.