Clinical Description and Diagnosis

In Infants

RSV infection is usually limited to the upper respiratory tract and sometimes accompanied by fever, in most healthy full-term infants. However, in 25% to 40% of RSV infections, the lower respiratory tract becomes infected and the infant may develop bronchiolitis or pneumonia. Very young infants, preterm infants, or high-risk infants and adults will have a greater chance of having a more severe infection (such as a lower respiratory tract infection). Asymptomatic infection is rare among infants.

Infants with a lower respiratory tract infection typically have a runny nose and a decrease in appetite before any other symptoms appear. Cough usually develops 1 to 3 days later. Soon after the cough develops, sneezing, fever, and wheezing may occur. In very young infants, irritability, decreased activity, and apnea may be the only symptoms of infection.

Most otherwise healthy infants who are infected with RSV do not need hospitalization. Those who are hospitalized may require oxygen, intubation, and/or mechanical ventilation. Most improve with supportive care and are discharged in a few days.

In Adults

Symptomatic RSV infections may occur in adults, particularly in healthcare workers or caretakers of small children. Disease usually lasts less than 5 days, and symptoms are usually consistent with an upper respiratory tract infection and can include a runny nose (rhinorrhea), sore throat (pharyngitis), cough, headache, fatigue, and fever, but some high-risk adults, such as those with certain chronic illnesses or immunosuppression, may have more severe symptoms consistent with a lower respiratory tract infection, such as pneumonia.