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: "One pilot study (NCT05583357) included 20 participants randomized at 1:1"
Comment: Allocation sequence probably random. No information on allocation concealment |
| Deviations from intervention |
Some concerns |
Quote: “open-label trial”
Deviations from intended intervention arising because of the study context: " Participants received the investigational vaccines according to the randomization table." "One participant allocated to the CoronaVac group received the V-01D-351". This deviation was not balanced and could affect the outcome. Nevertheless, this domain was rated as some concern as it is impossible to distinguish deviation because of trial context and deviation because of intervention effect. Per-protocol analysis was performed. One participant allocated to the CoronaVac group was analyzed in the V-01D-351 group. As we are assessing the effect of assignment to intervention (intention-to-treat effect), we considered that the data were analyzed inappropriately. There was probably substantial impact of failure to analyze participants according to their randomized assignment due to 1 participant cross-over. Risk assessed to be some concerns for the outcomes: Neutralizing antibody assay GMT. nAb Seroconversion rate Omicron. Neutralizing antibody assay GMT Omicron. Adverse events; Serious adverse events. |
| Missing outcome data |
Low |
Comment: 20 participants randomized; 20 participants analyzed.
Data available for all or nearly all participants randomized. Risk assessed to be low for the outcomes: Neutralizing antibody assay GMT. nAb Seroconversion rate Omicron. Neutralizing antibody assay GMT Omicron. Adverse events. Serious adverse events. |
| 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 NEUTRALIZING ANTIBODY ASSAY GMT, nAb SEROCONVERSION RATE OMICRON, NEUTRALIZING ANTIBODY ASSAY GMT OMICRON Observer-reported outcome not involving judgement. Risk assessed to be low for the outcomes: Neutralizing antibody assay GMT. nAb Seroconversion rate Omicron. Neutralizing antibody assay GMT Omicron ADVERSE and SERIOUS ADVERSE EVENTS The authors reported on adverse events that may contain both clinically- and laboratory-detected events, which can be influenced by knowledge of the intervention assignment, but is not likely in the context of the pandemic. Risk assessed to be some concerns for the outcomes: Adverse events. Serious adverse events. |
| Selection of the reported results |
Some concerns |
Comment: the protocol and statisitical plan were not available. The retrospective registry was available (Dated October 17, 2022).
No information on whether the result was 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 outcomes: Neutralizing antibody assay GMT. nAb Seroconversion rate Omicron. Neutralizing antibody assay GMT Omicron. Adverse events. Serious adverse events. |
| Overall risk of bias |
Some concerns |