Results
In the initial search, 1653 papers were retrieved from the PubMed, EMBASE, Scopus, Web of Science, Cochrane Central, Google Scholar, MedRxiv, and clinicaltrials.gov. After removal of duplicates, 1539 title and abstracts were screened for the eligibility criteria. As for the remaining 18 articles, a paper was excluded if it met other inclusion criteria but did not report the mean and SD of the viral load or an accurate Ct value before and after the intervention. Excluded studies and reasons for exclusion are listed in Table Excluded studies and reasons for exclusion