palivizumab

Palivizumab is a humanized monoclonal antibody that targets the fusion (F) protein of respiratory syncytial virus (RSV). It is used as passive immunoprophylaxis to reduce the risk of hospitalization due to RSV lower respiratory tract infection in high-risk infants and young children. It is not a vaccine.

Palivizumab binds to RSV F protein on the surface of the virus, blocking viral entry into host cells and neutralizing infectious particles. By providing circulating antibodies, it offers temporary protection during the RSV season.

Indications include prophylaxis in certain high-risk populations, such as preterm infants and those with chronic Lung disease of prematurity or hemodynamically significant congenital heart disease. Dosing is by weight and given as an intramuscular injection, typically 15 mg/kg monthly during the RSV season for about five months; local guidelines may vary.

Palivizumab is administered intramuscularly, commonly under the brand name Synagis. It is reserved for prevention in individuals at high risk of severe RSV disease and is not effective as treatment once infection has occurred. Contraindications include hypersensitivity to palivizumab or components.

Development and regulatory status: Palivizumab was approved by the U.S. FDA in 1998 and has since been marketed by MedImmune and its successors. It remains a costly preventive measure with cost-effectiveness dependent on patient risk profile and RSV season length.