Which virus is the most common etiological agent of viral respiratory disease in infants and children?

Respiratory syncytial virus (RSV) is the leading cause of viral respiratory infections in infants and young children. The virus is highly contagious and primarily spreads through respiratory droplets. RSV is known for causing bronchiolitis and pneumonia, particularly in children under the age of two. Its prevalence and impact on young populations make it the most significant viral agent in this demographic.

While other viruses, such as the measles virus, Coxsackie A virus, and Coxsackie B virus, can cause respiratory symptoms or illnesses, they do not have the same level of incidence or association with severe respiratory disease in children as RSV does. Measles primarily presents with a characteristic rash and is not predominantly a respiratory disease, while Coxsackie viruses are generally associated with other illnesses, including hand-foot-and-mouth disease and myocarditis, rather than primarily causing respiratory issues. This distinction underscores RSV's unique role as the most common etiological agent for viral respiratory disease in infants and children.