| O'Brien 2021 |
Low risk of bias |
Participants were randomised via an Interactive Web Response System (IWRS) and the allocation sequence was concealed. There are no baseline differences that would suggest a problem with randomisation. |
Low risk of bias |
Both participants and those delivering the intervention were unaware of the assigned intervention received, and the analysis was appropriate. |
Low risk of bias |
Data of nearly all SARS‐CoV‐2 seropositive, negative and sero‐undetermined participants at baseline were analysed. |
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 unaware of the intervention received. |
Low risk of bias |
The data that produced this result was analysed in accordance with the pre‐specified analysis plan and the outcome was reported as planned in the protocol. Participants including SARS‐CoV‐2 seropositive and sero‐undetermined participants were analysed together. |
Low risk of bias |
For this outcome, there is a low risk of bias for all the domains. |
