The organism that causes RSV is transmitted from person to person through respiratory droplets when an infected person coughs or sneezes. Transmission can also result from direct or indirect contact with the nasal or oral secretions of an infected person. RSV can survive on surfaces, such as tables and cribs, for several hours. The virus is spread when a person touches a contaminated surface and then rubs his or her eye or nose.

Signs and symptoms of RSV usually occur within 4 to 6 days of exposure. Antibody titers seem to indicate that few children younger than age 4 escape contracting some form of RSV, even if it’s mild. In fact, RSV is the only viral disease whose maximum impact is during the first few months of life (the incidence of RSV bronchiolitis peaks at age 2 months). School-age children, adolescents, and young adults with mild re-infections are probably the source of infection for infants and young children.

This virus creates annual epidemics during the late winter and early spring in regions with a temperate climate and during the rainy season in the tropics. It can also be seen in immunocompromised adults, especially patients with bone marrow transplants.

Young children, especially infants, are at increased risk for bronchiolitis, tracheobronchitis, and pneumonia. The child may experience periods of apnea and respiratory failure requiring intubation and mechanical ventilation. Otitis media is a less severe complication of RSV in infants and young children.

The clinical features of RSV infection vary depending on the severity of illness. Initial signs and symptoms may include a runny nose and diminished appetite. Fever, coughing, sneezing, and audible wheezing may develop 1 to 3 days later. Irritability, decreased activity, and breathing difficulties may be the only findings in very young infants. Nasal flaring, retraction, cyanosis, and tachypnea may be present if respiratory involvement is severe. Other findings vary. If otitis media develops, a hyperemic eardrum may be revealed on otoscopic examination.