Study characteristics and risk of bias assessment
The studies were conducted in the USA, Puerto Rico, Brazil, and
Argentina and included individuals with mild or moderate
laboratory-confirmed SARS-CoV-2 infection. All trial protocols were
registered on ClinicalTrials.gov, had a parallel design, and were
classified as Phase 2 or Phase 3. Population characteristics, dosage of
nitazoxanide, outcomes of interest, and the time of outcomes assessment
are detailed in Table 1. Most trials evaluating nitazoxanide as
treatment for patients with COVID-19 had a low risk for selection,
performance, detection, attrition, and information bias. Two studies
were classified as high-risk for reporting bias [16,17] and two
studies as high-risk for operational bias [15,16] (eFigure 2;
supplementary file).