Signs and symptoms of respiratory syncytial virus infection typically appear about four to six days after exposure to the virus. In adults and older children, RSV usually causes mild cold-like signs and symptoms. These include:

  • Congested or runny nose
  • Dry cough
  • Low-grade fever
  • Sore throat
  • Mild headache

In severe cases

Respiratory syncytial virus can lead to a lower respiratory tract illness such as pneumonia or bronchiolitis — an inflammation of the small airway passages entering the lungs. Signs and symptoms may include:

  • High fever
  • Severe cough
  • Wheezing — a high-pitched noise that's usually heard on breathing out (exhaling)
  • Rapid breathing or difficulty breathing, which may make the child prefer to sit up rather than lie down
  • Bluish color of the skin due to lack of oxygen (cyanosis)

Infants are most severely affected by RSV. They may markedly draw in their chest muscles and the skin between their ribs, indicating that they're having trouble breathing, and their breathing may be short, shallow and rapid. They may cough. Or they may show few, if any, signs of a respiratory tract infection, but will eat poorly and be unusually lethargic and irritable.

Most children and adults recover from the illness in one to two weeks. But in young babies, infants born prematurely, or infants or adults who have chronic heart or lung problems, the virus may cause a more severe — occasionally life-threatening — infection that requires hospitalization.

When to see a doctor

Most cases of respiratory syncytial virus infection aren't life-threatening.

Seek immediate medical attention if your child — or anyone at risk of severe disease — experiences difficulty breathing, runs a high fever or turns blue, particularly on the lips and in the nail beds.

Jul. 29, 2011