| Bias | Author's judgement | Support for judgement |
| Randomization |
Some concerns |
Comment: No information about allocation concealment methods. Quote: "Eligible participants were sequentially assigned a randomisation number, according to a blocked randomisation list (block size 4) generated by an independent statistician using SAS software (version 9.4) Pre-existing adenovirus type-5 neutralising antibody is slightly higher in the experimental arm". |
| Deviations from intervention |
Low |
Comment: Double blind study. There is no evidence of deviation from the intended intervention that arose because of the trial contextÂ’ (i.e., no cross-over; Pre-existing adenovirus type-5 neutralising antibody is slightly higher in the experimental arm) . Outcome data were analyzed by using intention-to-treat analysis. |
| Missing outcome data |
Low |
Comment: 508 randomized/508 analyzed. Risk assessed to be "low" for all outcomes. |
| Measurement of the outcome |
Some concerns |
Comment: Most outcomes are observer-measured and do not involve clinical decision-making. Risk assessed to be "low" for the outcomes: SARS-RBD-specific antibodies Seroconversion, SARS neutralising antibodies seroconversion. Risk assessed to be "some concerns" for the outcomes: Adverse events, Serious adverse events. |
| Selection of the reported results |
Low |
Comment: The protocol was available. The statistical analysis plan was included in the protocol. Data for the outcomes at day 14, 28, but not for 6 months. Risk assessed to be "low" for all outcomes. |
| Overall risk of bias |
Some concerns |