[Smilliam]

AFAIK, monoclonal antibodies are a valid and approved treatment, but a vaccine is much more of a prophylactic measure. Part of managing a pandemic is avoiding a huge crunch on the medical system (like we're currently living). Vaccines help keep people out of the hospital to begin with.

Even if we were interested in using monoclonal antibodies as a prophylactic, the current monoclonal antibody treatments that we have available are delivered via IV infusion. That's much more time-consuming and resource intensive than two vaccine shots imo.