The goal of this clinical research study is to learn if ribavirin can help to control RSV in
patients with immune systems that have been weakened by a stem cell transplant. Researchers
also want to compare the effectiveness of the drug when it is given by mouth to when it is
inhaled. The safety of the drug in both methods of delivery will be studied.
Ribavirin is designed to prevent the RSV virus from making more copies of itself in the body.