| PROVENT |
Low risk of bias |
Participants were randomized via random number generation and the allocation sequence was concealed. There are no baseline differences that would suggest a problem with randomization. |
Low risk of bias |
Participants could be unblinded to consider vaccination, but percentages of participants with data that were unblinded were
balanced between the groups. The analysis was appropriate. |
Low risk of bias |
Data for this outcome was not available for all participants (5197/5197 participants randomized). |
Low risk of bias |
The measurement of the outcome was appropriate, and it is unlikely that it differed between intervention groups. The outcome assessors were probably unaware of the intervention received. |
Some concerns |
There is a trial protocol, which provided details of the pre‐specified outcomes, but the 6 months follow‐up was not pre‐specified. |
Some concerns |
For this outcome, there is a low risk of bias from randomisation process, deviations from intended interventions, missing outcomes, measurement of the outcome. There are some concerns for bias due to selection of reported results. |
