Data extraction.
Data extraction was done using an excel spreadsheet developed for the
purpose. We collected data on the trial registration, year/month of
commencement, registration body, the status of the trial, type of study
(vaccine trial/therapeutic trial), and the candidate drugs. We collated
only the agents in the different trials and analysed them in the
frequency table shown in Appendix 1 to show the most common
drugs under investigation across different trials.