RSV stands for Respiratory Syncytial Virus, which is a common respiratory virus that infects the lungs and breathing passages. It is so common that most children have been infected with the virus by age 2. RSV usually causes mild, cold-like symptoms, and most people recover in a week or two. However, some people with RSV infection, especially older adults and infants younger than 6 months of age, may need to be hospitalized if they are having trouble breathing or are dehydrated.

The signs and symptoms of RSV infection most commonly 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, such as a congested or runny nose, dry cough, low-grade fever, sore throat, sneezing, and headache. In severe cases, RSV infection can spread to the lower respiratory tract, causing pneumonia or bronchiolitis, which is inflammation of the small airway passages entering the lungs. Signs and symptoms of severe RSV infection may include fever, severe cough, wheezing, rapid breathing, or difficulty breathing.

If your child gets a fever after having a cold or has a high fever, has a cough or other symptoms that get worse, is having trouble breathing, or shows signs of dehydration, such as fewer wet diapers than usual, you should call your healthcare provider. If your child is struggling to catch their breath, is very drowsy, or has lips or fingernails that look blue, you should get medical help right away.