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: "Randomized controlled clinical trial (1:1). Once the sample was consolidated, each patient was assigned an ID corresponding to a number from 1 to 234. The selection to each group was performed through a random number generation process by an Excel spreadsheet. Then, 117 of them were randomly selected to generate the CG and EG." Comment: Allocation sequence random. No information on allocation concealment. |
| Deviations from intervention |
Low |
Quote: "Masking: None (Open-label)" (registry)
Comment: Unblinded study (participants and personnel/carers). Deviations from intended intervention arising because of the study context: No participant cross-over. No co-interventions of interest (vaccines) were available at the time of the study. Hence, deviations did not arise because of the trial context. Data for the outcomes were analyzed using intention-to-treat analysis. This method was considered appropriate to estimate the effect of assignment to intervention. Risk assessed to be low for the outcomes: Confirmed COVID-19. Symptomatic confirmed COVID-19. Mortality. |
| Missing outcome data |
Low |
Comment: 234 participants randomized; 234 participants analyzed. Data available for all participants randomized. Risk assessed to be low for the outcomes: Confirmed COVID-19. Symptomatic confirmed COVID-19. Mortality. |
| Measurement of the outcome |
Some concerns |
Comment: Method of measuring the outcome probably appropriate.
Measurement or ascertainment of outcome probably does not differ between groups. Unblinded study (outcome assessor). CONFIRMED COVID, MORTALITY: Mortality and Confirmed COVID are observer-reported outcomes not involving judgement. Risk assessed to be low for the outcomes: Confirmed COVID-19. Mortality. SYMPTOMATIC CONFIRMED COVID: Although some symptoms were laboratory-detected, assessing most of the symptoms required judgement which could be affected by knowledge of intervention receipt, but was not considered likely in the context of a pandemic. Risk assessed to be some concerns for the outcome: Symptomatic confirmed COVID-19. |
| Selection of the reported results |
Low |
Comment: The protocol (dated October 2020) was available. The trial registry was also available, but was retrospective.
Outcomes were pre-specified in the protocol. Results were not selected from multiple outcome measurements or analyses of the data. Trial analyzed as pre-specified. Risk assessed to be low for the outcomes: Confirmed COVID-19. Symptomatic confirmed COVID-19. Mortality. |
| Overall risk of bias |
Some concerns |