RSV Epidemiological Surveillance

Respiratory syncytial virus (RSV) is a major cause of acute lower respiratory tract infection worldwide. Most children infected with RSV typically show mild respiratory symptoms. In newborns and infants, the typical clinical manifestations are bronchiolitis and pneumonia: the first is usually self-limiting, but accounts for a significant number of hospitalizations and admissions to the pediatric intensive care unit.Before the COVID-19 pandemic, RSV was typically described as a seasonal virus, characterized by a predictable epidemiological pattern, depending on the geographic area and climate. Due to restrictive measures adopted during the pandemic, many authors reported an initial reduction in RSV circulation, followed by an out-of-season surge of RSV as the measures adopted during the COVID-19 pandemic loosened. Epidemiological surveillance suggests that this trend in the epidemic wave affected not only children, but also adults, in particular the elderly. On the other hand, newly introduced prophylactic measures, such as nirsevimab administration to newborns and infants, are positively affecting the global picture. This Special Issue provides a comprehensive scenario of the epidemiological trend of RSV before, during, and after the COVID-19 pandemic. Furthermore, it represents a starting point for designing future preventive strategies to reduce RSV spread in both children and adults.