Data extraction and sources
One author (DJ) extracted data using a pre-standardized form. Quality control was performed by re-extracting data from 15% of the included trial registers. Information on the trial ID, scientific title, date of registration, recruitment status, patient population and funding sources were extracted from the WHO-ICTRP database. Information on the country where the trials were planned to be conducted was extracted primarily from the WHO-ICTRP database and completed using the trial register data when appropriate.
The trial’s register was accessed and provided addition information to characterize the RCTs according to:
The efficacy/effectiveness outcomes were classified as clinical (e.g., improvement or recovery of respiratory symptoms) or surrogate outcomes (e.g., viral load, biomarkers, etc.). The mode of data collection of the adverse events was classified as “systematic assessment ” when specific ascertaining methods to detect the occurrence of adverse events were described by the use of checklists, questionnaires, or laboratory tests at regular intervals, and as “non-systematic assessment ” when the detection methods relied on the spontaneous report of adverse events by clinicians or participants15.