A contact notes, "the regeneron drug, which is an infusion of a cocktail of two different monoclonal antibodies" would require that he be "in the hospital with an IV and cardiac and oxygenation monitoring."

So more invasive than the daily aspirin he's also supposed to be on.

Not gonna describe possible side effect (again, per contact), but suffice it to say you'd want to be in hospital in case things went wrong.

From contact: "They could administer in WH, but risk is anaphylaxis, so they would need to be somewhere they could intubate and support his circulation if he were to go into shock....This does not indicate he is critically ill."