Immunoprophylaxis and the control of respiratory syncytial virus disease.

Abstract

Respiratory syncytial virus (RSV) remains one of the most important infectious causes of hospitalization in infants and children. This enveloped, RNA virus produces predictable yearly outbreaks of disease that typically peak between January and February in countries in the northern hemisphere.1 The outcome of RSV infection varies from mild upper respiratory tract infection in approximately 75% of infected infants and young children to severe life-threatening disease in a small percent of infected patients.2 In the United States, RSV lower respiratory tract infection accounts for nearly 50% of hospitalizations due to bronchiolitis and 25% of hospitalizations due to pneumonia.1 Serologic surveys suggest that by 2 years of age, more than 90% of all children have been infected by RSV.3 Whether RSV infection early in life predisposes to subsequent reactive airway disease remains an unanswered question. Reinfection is common, indicating that immunity to RSV following natural infection is less than complete.4-6 RSV lower respiratory tract disease occurs primarily in infants under 2 years of age; most infants who require hospitalization are previously healthy infants less than 6 months of age. Premature infants, infants born with congenital heart disease, and those with chronic lung disease (such as bronchopulmonary dysplasia [BPD]) constitute additional high-risk groups with high rates of hospitalization due to RSV infection.7-13 A recent report describes RSV mortality rates among such hospitalized infants of 4% to 5%.14Pre-engraftment bone marrow transplant recipients, solid organ transplant recipients, and lymphopenic children receiving chemotherapy appear to suffer even higher mortality rates, although prospective data are not available.15 Morbidity in these groups is also great; the average hospital stay and intensity of care for such children may be several times that of previously healthy infants. Despite the importance of RSV as a pathogen in the pediatric age group, …