When a respiratory syncytial virus (RSV) infection affects the nose and throat (upper respiratory system), symptoms are usually mild and resemble those of the common cold. They include:

• Cough.
• Stuffy or runny nose.
• Mild sore throat.
• Earache.
• Fever, usually at the beginning of the illness. A high fever does not mean the illness is more severe.

Babies may have additional symptoms, including:

• A decreased interest in their surroundings.
• Listlessness and sleepiness.
• Fretfulness (irritability) and not sleeping well.
• Poor feeding.
• Apnea, where breathing stops for about 15 to 20 seconds. This usually occurs only in babies who were born prematurely and who also have a history of apnea.

It is difficult to distinguish between a common cold and RSV infection. Unless you or your child has an increased risk of having complications from RSV, it usually is not important to know which virus causes symptoms.

RSV infection can also lead to bronchiolitis and/or pneumonia.

Symptoms of these complications include:

• Difficulty breathing, which may include breathing more rapidly than normal.
• Wheezing.
• Coughing that is getting worse. A child may choke or vomit from intense coughing that may be dry or loose (producing mucus).
• Lethargy, increased tiredness, decreased interest in surroundings, or loss of interest in food.