| Bias | Author's judgement | Support for judgement |
| Randomization |
Low |
Quote: "Participants were assigned a computer-generated randomisation code" "The master randomisation list was uploaded to the Interactive Web Response System, which contained the randomisation number and intended allocation. The depot manager uploaded the kit code list and assigned the kits to the sites that had the kit codes and the allocation groups. At the site level, the system set the randomisation number and the allotment of the kit without displaying the true group allocation, and the system allocated the same treatment arm for the second visit. A block size of four was utilised. An unblinded Contract Research Organization (CRO), Sclin Soft Technologies, was involved in randomisation for the study." Comment: Allocation sequence random. Allocation concealed. Imbalances in baseline characteristics appear to be compatible with chance. |
| Deviations from intervention |
Low |
Quote: "The appearance, color, and viscosity were identical across all formulations." Quote: "Participants, investigators, study coordinators, study-related personnel, and the sponsor were blinded to the treatment group allocation". Quote: "The blinded study nurse was responsible for vaccine preparation and administration. Each vial contained a unique code that ensured appropriate blinding." Comment: Blinded study (patients, nurses, physicians, and investigators). No participant cross-over. Data were analyzed using intention-to-treat analysis. Risk assessed to be low for the outcomes: Serious adverse events. |
| Missing outcome data |
Low |
Comment: Data from interim analysis. 380 patients randomized; 361 patients analyzed on day 56. Data available for all or nearly all participants. Quote: "The retention rates at day 56 were 96.8% and 93.2% in the 3 mcg and 6 mcg with Algel-IMDG groups, respectively". Reported reasons for missing data were withdrew consent (n=9) and lost to follow-up (n=5); reasons for missing outcome data were not reported for 5 participants. Risk assessed to be low for the outcome: Serious adverse events. |
| Measurement of the outcome |
Low |
Comment: Blinded study (outcome assessor). Risk assessed to be low for the outcome: Serious adverse events. |
| Selection of the reported results |
Low |
Comment: The prospective trial registry was available. Serious adverse events was listed as outcome with timepoints specified in one of the registries (CTRI, but not NCT). No information on whether the result was selected from multiple outcome measurements or analyses of the data. Risk assessed to be low for the outcome: Serious adverse events. |
| Overall risk of bias |
Low |