Study selection and eligibility criteria
Two reviewers (P.R.M.-F. and E.M.N.-J.) independently screened the search results and identified studies that were potentially relevant based on their title and abstract. Relevant studies were read in full and selected according to eligibility criteria. Disagreements between the two reviewers were resolved by consensus.
The following elements were used to define eligibility criteria: (1) Population: individuals with laboratory-confirmed SARS-CoV-2 infection; (2) Intervention: nitazoxanide; (3) Comparison: placebo; (4) Outcomes: positive RT-PCR status, composite measure of disease progression (severe COVID-19, ICU admission or invasive mechanical ventilation), death, serum biomarkers of inflammation (C-reactive protein, IL-6, and IL-8), and any adverse events; (5) Study type: blinded, placebo-controlled, RCTs. Eligible studies must report at least 1 of the outcomes of interest. Potential overlapping populations, open-label trials, and observational studies were excluded. Trials testing drug associations were also excluded.