This is a dose optimisation study in healthy adults aged 18-30 who will be experimentally
inoculated with SARS-CoV-2. The aim is to cause PCR-confirmed upper respiratory infection in
the majority of challenged individuals with minimal or no illness, providing data on the
course of COVID-19 and the immune response to SARS-CoV-2 infection. This will establish an
optimised dose and study design that will then be used to evaluate the efficacy of treatment
and vaccine candidates plus level and duration of immune protection in follow-on trials.