December 26, 2020

Background Information: With rising cases, an increasing death toll, and a significant strain on hospital systems globally, the COVID-19 pandemic seemed to have no end in sight. The aggressive pursuit of a vaccine has led to multiple clinical trials starting before the end of this year. In fact, there are 48 vaccines under clinical evaluation and 11 of these are currently being evaluated in phase 3 clinical efficacy trials.1 Among those includes, the replication-deficient chimpanzee adenoviral vector developed at Oxford University (ChAdOx1). Following the initiation of a phase 1 clinical trial in the UK (COV001), three additional randomized controlled trials were initiated across the UK (COV002), Brazil (COV003) and South Africa (COV005). Upon completion of enrollment, the authors of the following paper sought to perform a combined interim analysis of the four trials to assess ChAdOx1’s efficacy and safety