children's hospital of philadelphia and fda vaccine advisory committee. as a physician, what is the biggest barrier to doctors recommending these life-saving antibodies? >> i think two things. it's infrastructure. and also knowledge. monoclonal antibodies work if given early in infection. when viral replication is at its peak. it doesn't work later in infection by the time you're in the hospital and you have symptoms. it's really too late. so -- severe symptoms. it's not a good infrastructure for that. giving an intravenous drug really outside the hospital. we're very good at giving drugs inside the hospital. outside is much tougher. and lack of knowledge. people don't realize how well these monoclonal antibodies work in those groups at high risk in preventing serious and occasionally fatal illness. >> we're still seeing about 1600 deaths a day in the united states. should the biden administration be pushing this more? should hospitals be requesting more vials of this life-saving