Z29.11 Code – Prophylactic Immunotherapy for RSV Prevention Call Us Leave a Message Z29.11 is the ICD-10 code for Encounter for prophylactic immunotherapy for respiratory syncytial virus (RSV) which essentially means it is the medical billing code used when a patient receives a preventative treatment, like a monoclonal antibody injection, protects against RSV infection; essentially, a preventative RSV immunotherapy treatment. What is Z29.11? Meaning: This code signifies a medical encounter