Respiratory syncytial virus - from discovery to vaccines.

Respiratory syncytial virus (RSV) is a leading cause of hospitalization among infants and young children in the USA and worldwide. As the primary etiological agent of bronchiolitis and pneumonia in infants, RSV is the second leading cause of infant mortality after the neonatal period, causing over 200,000 deaths annually. Despite its significant impact, and although several antiviral candidates are under development, no specific therapy is currently available, and treatment remains largely supportive. While premature infants and those with chronic lung disease, congenital heart defects, Down syndrome or neuromuscular disorders are at increased risk for severe disease, the majority of hospitalizations occur in previously healthy, term-born infants. More than 97 % of childhood deaths due to RSV occur in low- and middle-income countries. RSV infections are also responsible for a substantial outpatient healthcare burden and might lead to long-term complications such as recurrent wheeze or asthma. Notably, RSV also imposes a considerable disease burden on older adults and immunocompromised individuals. The recent approval of recombinant bivalent RSV vaccines for high-risk adults and pregnant women, along with an extended half-life monoclonal antibody designed to prevent severe infection during the first 6 months of life, represents a major advancement in prevention strategies. This review explores the history, viral features and host response and clinical presentation and summarizes recent developments in RSV prevention.