Note: The risk of bias by domain corresponds to the highest risk of bias among outcomes by domain.
The overall risk of bias corresponds to the overall highest risk of bias assessed among outcomes.
Bias | Author's judgement | Support for judgement |
Randomization |
Some concerns |
Quote: "A block randomization method was used to randomize the study participants into two groups that result in equal sample size. This method was used to ensure a balance in sample size across groups over the time and keep the number of participants in each group similar at all times."
Comment: Allocation sequence probably random. No information on allocation concealment. |
Deviations from intervention |
Some concerns |
Quote: “double blind randomized controlled clinical trial” (for the report that includes both treatment and prevention groups).
Comment: No information reported on blinding of the preventive RCT groups. While the report overall says it was double blind, it is unclear whether this also applies to the prevention groups as the control arm did not receive medication/placebo. Hence probably not blinded (participants and personnel/carers). Deviations from intended intervention arising because of the study context: No information on participant cross-over (no flow chart). No information on administration of co-interventions of interest: antivirals, biologics, corticosteroids. Hence, no information on whether deviations arose because of the trial context. No information on whether participants were analyzed according to their randomized groups (no flow-chart). Probably no substantial impact of failure to analyze participants according to their randomized groups (unlikely there was impactful crossover). Risk assessed to be some concerns for the outcome: Confirmed COVID-19. |
Missing outcome data |
Low |
Comment: 200 patients randomized; 200 patients analyzed.
Data available for all participants. Risk assessed to be low for the outcome: Confirmed COVID-19. |
Measurement of the outcome |
Low |
Comment: Method of measuring the outcome probably appropriate.
Measurement or ascertainment of outcome probably does not differ between groups. Unclear blinding of outcome assessor. Incidence of confirmed COVID-19 is an observer reported outcome not involving judgement. Risk assessed to be low for the outcome: Confirmed COVID-19. |
Selection of the reported results |
Some concerns |
Comment: The trial registry was available, but registration occurred after the study was completed.
No information on whether the results were selected from multiple outcome measurements or analyses of the data. No information on whether the trial was analyzed as pre-specified. Risk assessed to be some concerns for the outcome: Confirmed COVID-19. |
Overall risk of bias |
Some concerns |