First, as disclosure, I initiated my position on VIR several days back, and can not complain about this deal.
I am very curious what epitope does VIR-7831 and VIR-7832 target? Definitely, it is not epitope on spike-RBD, as does not intercept/block complexing of the spike with ACE2 receptor (cross-reactivity is not characteristic for RBD-epitope Abs due to difference in binding to ACE2 receptor). Fc-mediated activation of effector-B cells obviously indicate antibody mediated viro-toxicity.
I am not sure how will those Abs fire in prophylactic trial? Distribution upon SC-injection and retaining in lung/upper respiratory tract? Neutralizing anti-Abs is also unknown factor?