Controlled Human Infection to Speed Up SARS-CoV-2 Vaccine Development

Controlled human infection (CHI) studies have been performed previously with a range of virologic, bacteriologic, and parasitic agents, yielding important information on immunopathogenesis, duration of vaccine-induced immunity, and to define correlates of protection in healthy populations (1-3). CHI can also provide key safety, tolerability, immunogenicity, and efficacy data supporting vaccine research. Typically, in a CHI experiment, participants are given a test vaccine and are inoculated 2-4 weeks later with the pathogen of interest via the most physiologically relevant route of administration. Such experiments require only a few months to complete, and the number of participants enrolled is usually rather in the tens than in the hundreds, let alone in the thousands or ten-thousands needed for phase 3 Randomized Controlled Trials (RCTs).