Table 1.

Characteristics of the studies included

Author/year	Type of publication	Country	Setting	Sample (n)	COVID-19 diagnosis	Mouthrinse type	Experiment details	Primary outcome evaluated	Follow-up (time)
Gottsauner (2020)	Short communication	Germany	Hospital	10	Only patients with a positive RT-PCR test for SARS-CoV-2 within the last 72 hours were included in this study	H2O2	Patients were asked to gargle their mouth and throat with 20 mL 0.9% NaCl for 30 seconds in order to acquire a baseline oropharyngeal specimen for the SARS-CoV-2 real-time RT-PCR test. Immediately afterwards, patients had to perform a mouthrinse with 20 mL 1% H2O2 by gargling their mouth and throat for 30 seconds. Thirty minutes after this mouthrinse, another oropharyngeal specimen for the SARS-CoV-2 RT-PCR test was acquired by asking the patients to gargle their mouth and throat with 20 mL 0.9% NaCl for 30 seconds. The respective quantities of copies/mL of SARS-CoV-2 RNA were analysed by RT-PCR	Intraoral viral load in SARS-CoV-2 positive patients	30 minutes
Martínez Lamas (2020)	Short communication	Spain	Hospital	4	RT-PCR test	PI	Patients were asked to cough out saliva from their throat into a sterile container, and 2 mL of viral transport medium was added at baseline after which each participant rinsed their mouth with 15 ml of 1% PI for 1 minute. Afterwards, saliva samples were collected at 5 minutes, 1 hour, 2 hours and 3 hours	Salivary viral load of SARS-CoV-2 in patients with COVID-19	3 hours
Seneviratne (2020)	Original article	Singapore	Hospital	16	Positive nasal swabs for SARS-CoV-2 based on RT-PCR assay	PI CHX CPC	3 mL of saliva was collected by passive drool technique from all the COVID-19 patients enrolled at baseline and after rinsing their mouth with the corresponding mouthwash (PI, CHX, CPC or water). Three additional samples were obtained at 5 minutes, 3 hours and 6 hours	Salivary SARS-CoV-2 viral load in patients with COVID-19	6 hours
Yoon (2020)	Original article	Korea	Hospital	2	Real-time RT-PCR	CHX	During hospital days 3 and 6, patients were asked to collect saliva samples while being supervised by an investigator in order to obtain a baseline for the SARS-CoV-2 using real-time RT-PCR test. Immediately afterwards, patients performed a mouthrinse with CHX solution (0.12%, 15 mL) for 30 seconds. Serial saliva samples were collected at 1, 2 and 4 hours after the mouthrinse for the SARS-CoV-2 real-time RT-PCR test. The respective quantities of copies/mL of SARS-CoV-2 RNA were analysed by real-time RT-PCR	Viral dynamics in various body fluid specimens, such as nasopharyngeal swab, oropharyngeal swab, saliva, sputum and urine specimens, of two patients with COVID-19 from hospital day 1 to 9	4 hours
Schürmann (2021)	Miscellaneous	Germany	Hospital	34	RT-PCR test	Linolasept	Pharyngeal swabs were taken from all patients immediately before and 5 minutes after having gargled mouthwash for 1 minute. To investigate the time course of viral load development after gargling, additional pharyngeal swabs were taken from five patients at different time points: 0, 2, 4 and 6 hours. Real-time polymerase chain reaction (RT-qPCR) for the S-, N- and R-genes with cycle threshold for SARS-CoV-2 was performed	Viral load of SARS-CoV-2 in the saliva of COVID-19 patients	6 hours
Key: RT-PCR = reverse-transcription polymerase chain reaction; H2O2 = hydrogen peroxide; PI = povidone-iodine; CHX = chlorhexidine gluconate; CPC = cetylpyridinium chloride; NaCl = sodium chloride.