https://www.sciencedaily.com/releases/2020/07/200702100540.htm

Writing in a commentary on behalf of Accelerating COVID-19 Therapeutic Interventions and Vaccines's Vaccines Working Group, authors from the Walter Reed Army Institute of Research, University of Maryland School of Medicine, University of North Carolina School of Medicine and Henry M. Jackson Foundation for the Advancement of Military Medicine, detailed a series of scientific and ethical concerns and considerations required for robust controlled human infection models development. While CHIMs are unlikely to advance the timelines of current SARS-CoV-2 vaccines in advanced development, the authors argue, such tests may be able to accelerate later rounds of vaccine candidates.

Traditional vaccine development is typically linear, where animal then human testing informs a regulatory decision on vaccine licensure, finally allowing for mass production. In the face of the significant public health burden of COVID-19, the disease caused by SARS-CoV-2, vaccine developers have made unprecedented efforts to shorten timelines by compressing and overlapping these steps.