Respiratory Syncytial Virus Infection in Infants with Congenital Heart Disease and Treatment with Human Leukocyte lnterferone

Between 1980 and 1986, we observed lower respiratory-tract infection caused by respiratory syncytial virus (RSV) in 19 infants and young children with various forms of congenital heart disease. Of these, seven patients who presented with a severe illness were treated with intramuscular injections of 0.5 to 1 times 106 IU per day of human leukocyte interferon (IFN) for three to five days. Intrinsic IFN activity developed before treatment in three subjects. Viral isolation studies showed active RSV infection prior to treatment, and no infectious RSV was recovered one to four days after treatment. Although there were no obvious changes in the clinical course after IFN therapy, no deaths related to RSV infection occurred. Analysis of the different types of congenital heart disease showed that ventricular septal defect and/or patent ductus arter-iosus with pulmonary hypertension were associated with the most severe RSV illness. The therapeutic value of IFN may improve in this group of subjects if it is given without delay.