Palivizumab is a monoclonal antibody product containing antibody against respiratory syncytial virus alone. What follows for a live vaccine?

1. Antibody from any source can interfere with a live vaccine by blocking replication of the vaccine organism. 2. Immune globulins are polyclonal, containing antibody against many antigens, so they carry that risk. 3. A monoclonal product is directed against one antigen or a closely related group, so it cannot block an unrelated vaccine virus. 4. Palivizumab holds antibody against respiratory syncytial virus only, so the response to a live vaccine is unaffected. 5. Delaying or substituting the vaccine would be the response to a polyclonal antibody product, not a monoclonal one. 6. Complete vaccine failure describes interference at its worst, which is exactly what the single-antigen product avoids. _Source: CDC Epidemiology and Prevention of Vaccine-Preventable Diseases (Pink Book), section Passive Immunity_