Do hydrogen peroxide mouthwashes have a virucidal effect? A systematic review

BACKGROUND: The presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in saliva has alerted health professionals to the possibility of contamination by aerosols generated in a number of procedures. The indication of preoperative mouthwash containing 1% hydrogen peroxide for reducing the viral load of SARS-CoV-2 in saliva prior to oral procedures has been significantly disseminated through several citations and influenced various dental associations in the elaboration of dental care protocols during this pandemic period, including patients admitted to hospital wards and intensive care units. AIM: To Our aim was to perform a systematic review to answer the following question: does hydrogen peroxide mouthwash (at any concentration) have a virucidal effect? METHODS: The Cochrane, LILACS, PubMed, Scopus, and Embase databases were searched by using the following key-words: ‘hydrogen peroxide’, ‘mouthwash’, ‘mouth rinse’, ‘rinse’, ‘oral rinse’, ‘mouth bath’, ‘mouth wash’, and ‘mouth washes’. Reviews, letters to the editor, personal opinions, book chapters, case reports, congress abstracts, studies with animals and studies on mouthwash containing other compounds other than hydrogen peroxide were excluded. FINDINGS: During the initial search 1342 articles were identified on the five electronic databases. After excluding some duplicates, 976 articles remained. Only studies assessing the virucidal effect of hydrogen peroxide mouthwash were selected, regardless of publication date. CONCLUSION: After reading titles and abstracts, no article met the eligibility criteria. In conclusion, there is no scientific evidence supporting the indication of hydrogen peroxide mouthwash for control of the viral load regarding SARS-CoV-2 or any other viruses in saliva.