Table 2 Unblinding of clinical site personnel for emergency medical management

1. In the event of a medical emergency that directly affects the health status of the participant, it may become necessary to unblind allocation status to determine the specific treatment the participant has received while enrolled in the study. A medical emergency is defined as an event which necessitates immediate attention regarding the treatment of a participant.

2. Clinical site personnel (e.g. local principal investigators, co-investigators, and research coordinators) will contact one of the LOVIT principal investigators if they believe that unblinding of a study participant is medically necessary.

3. The LOVIT principal investigator will discuss the participant’s medical event with the clinical site personnel and determine if it is necessary to unblind her/him to the participant’s treatment allocation. At no time will the participant’s health be compromised or medical treatment delayed.

4. Once approved, the principal investigator or coordinating centre project leader will contact the designated unblinded research coordinator at the coordinating centre, who will provide the clinical site personnel with the participant’s vitamin C or placebo allocation. This information should be provided by telephone to reduce the risk of unblinding additional team members.

5. The unblinded research coordinator will complete the LOVIT unblinding log. The unblinded research coordinator may contact the research coordinator at the clinical site to request any additional information required to complete this log.

6. The unblinded research coordinator is not to unblind the principal investigators or any blinded members of the LOVIT team unless deemed necessary by the principal investigator. Similarly, clinical site personnel are also not to unblind any other members of the LOVIT study team (including the Methods Centre research coordinator, principal investigators, or any clinical site research personnel who were not unblinded) unless deemed necessary by the principal investigator(s).

7. LOVIT personnel must keep all information related to the individual unblinding cases confidential.

8. All cases of unblinding must be documented, including clinical site ID, study ID, date of unblinding, parties unblinded, and reason for unblinding.