Respiratory syncytial virus (RSV)

Respiratory syncytial virus (RSV) is an enveloped, single-stranded RNA virus from the Pneumoviridae family and the leading cause of lower respiratory tract infections, such as bronchiolitis and pneumonia, in infants and the elderly. The virus infects host cells through its surface glycoproteins, primarily the Fusion (F) protein and the Attachment (G) protein. The F protein is a class I fusion protein that undergoes a significant conformational shift from a metastable prefusion state to a stable postfusion state to facilitate viral-cell membrane fusion. This protein is the primary target for current prophylactic monoclonal antibodies, such as palivizumab and nirsevimab, as well as newly approved vaccines like Arexvy and Abrysvo. The G protein mediates initial attachment by binding to host receptors, including CX3CR1 and heparan sulfate proteoglycans, while also acting as an immune decoy. Therapeutic interventions focus on neutralizing these proteins to block viral entry or inhibiting the viral RNA-dependent RNA polymerase (L protein) to arrest replication.

Other names

Human respiratory syncytial virusHuman orthopneumovirushRSVRSVRespiratory syncytial virus infection

The primary mechanism of action for RSV therapeutics involves fusion inhibition, where drugs bind to the prefusion conformation of the viral F protein to prevent membrane fusion and viral entry. Monoclonal antibodies also work through viral neutralization by blocking the attachment of G or F proteins to host cell receptors. Additionally, antiviral drugs like ribavirin act as nucleoside analogs to inhibit the viral RNA-dependent RNA polymerase (L protein), thereby disrupting viral genome replication and transcription.