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 |
Low |
Quote: "The randomization number for each vaccination schedule wasgenerated by SAS software (version 9.4), and stratified block ran-domization (block size 8) by subgroups, generated by an indepen-dent statistician, was used. Within each randomization block, theratio of vaccine to placebo was 3:1. A randomization numberwas sequentially assigned to each participant, and then the partic-ipant was injected with a vaccine or placebo with the same num-ber. " Comment: Sequence generation random Sequence allocation concealed. |
| Deviations from intervention |
Low |
Quote: "double-blinded" Comment: Blinded study (participants, personnel, investigators). All randomized participants who received at least one dose were analysed for safety outcomes. As we are assessing the effect of assignment to intervention, the analysis method performed on these safety outcomes, was considered appropriate. Risk assessed to be low for outcomes: Local adverse events. Systemic adverse events. Adverse events. Serious adverse events. |
| Missing outcome data |
Low |
Comment: 192 randomized/192 analysed for ITT safety outcomes. In the per protocol immunogenicity analysis there was 1 participant excluded (0.5% of the sample). No information about the reason for exclusion, however, these are not likely to have influenced the result. Risk assessed to be low for outcomes: Local adverse events. Systemic adverse events. Adverse events. Serious adverse events. |
| Measurement of the outcome |
Low |
Method of measuring the outcome probably appropriate. Measurement or ascertainment of outcome probably does not differ between groups. Blinded study (outcome assessor). Risk assessed to be low for outcomes: Local adverse events. Systemic adverse events. Adverse events. Serious adverse events. |
| Selection of the reported results |
Some concerns |
Comment: Protocol and statistical plan not available.Resgistry was available but retropective 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 outcomes: Local adverse events. Systemic adverse events. Adverse events. Serious adverse events. |
| Overall risk of bias |
Some concerns |