Respiratory syncytial virus (RSV) is the leading cause of
respiratory tract infection in infants and young children throughout the world. Although
preterm birth has been considered for years the major risk factor for severe disease and hospitalization, recent findings indicate that prematurity is not a necessary condition, but one of the independent risk factors for severe
RSV infection, together with chronic
lung diseases,
congenital heart disease and immunodeficiency. Furthermore, over 50% of infants hospitalized for
RSV infections during the first year of life are healthy, full-term newborns, suggesting that other environmental and individual factors may be involved. Unfortunately, there is still no specific
therapy against
RSV infection and therefore prophylactic measures seem to be the only intervention to avoid disease complications. No safe and effective
RSV vaccine is available for the prevention of serious
RSV infection. Therefore, in addition to hygienic measures, the only approach is passive immunoprophylaxis with humanized monoclonal anti-RSV
antibodies, such as
palivizumab that have been developed for clinical use. Because of the high cost of these
antibodies, a better definition of the individual risk profile for severe
RSV infection and timing of administration is needed for optimal effectiveness and careful use of limited health care resources. In this article, we have reviewed the clinical and pharmacological aspects of immunoprophylaxis with
monoclonal antibodies for preventing
RSV infection in high-risk infants.