pediatrics
Respiratory Syncytial Virus (RSV) and Human Metapneumovirus Infections
Respiratory syncytial virus (RSV)
RSV is an RNA virus, classified as a pneumovirus. Subgroups A and B have been identified. RSV is the most common cause of lower respiratory tract illness in young infants and is responsible for>50,000 hospitalizations annually in the United States in children under the age of 5 years. RSV is ubiquitous; almost all children are infected by age 4 years. Outbreaks typically occur annually in winter or early spring in temperate climates. However, RSV and other respiratory virus circulation patterns were disrupted during the COVID-19 pandemic ( Reference ). Because the immune response to RSV does not protect against reinfection, the attack rate is approximately 40% for all exposed people. However, antibody to RSV decreases illness severity. 