Symptoms of RSV are similar to other respiratory infections. Illness begins 4 to 6 days after being exposed to the virus. In adults and older children, typical RSV symptoms include a low-grade fever, congested or runny nose, cough, sore throat, headache, fatigue, and occasionally wheezing. In children younger than age 2, RSV can cause a lower respiratory tract illness such as bronchiolitis or pneumonia; more severe cases can result in respiratory failure. For people with severe illness, symptoms may include a worsening croupy cough, unusually rapid breathing, difficulty breathing, and a bluish color of the lips or fingernails caused by low levels of oxygen in the blood. RSV can cause middle ear infections (otitis media) in preschool children.
The majority of children hospitalized for an RSV infection are under the age of six months. The elderly (those 65 years of age and older), premature infants, persons with chronic lung or heart problems, and persons with weak immune systems are at higher risk for developing serious illness. Those who are exposed to tobacco smoke, attend daycare, live in crowded conditions, or have school-aged siblings could also be at higher risk.