This article was updated on October 3, 2025.

Respiratory syncytial virus, or RSV, is a common respiratory virus that usually causes mild, cold-like symptoms. Infection with RSV is common among young children and usually begins as a mild cold, but can cause severe breathing problems in premature babies, as well as infants and toddlers under the age of two who have chronic lung disease and chronic heart disease. Almost all children get RSV at least once before they are two years old.

RSV is the most common cause of bronchiolitis (inflammation of the small airways in the lung) and pneumonia (infection of the lungs) in children younger than 1 year of age in the United States.

What are the symptoms of respiratory syncytial virus?

Typically, RSV causes a cold, but it can also lead to bronchiolitis or pneumonia.

Symptoms of an RSV cold include:

• Fever (temperature of 100.4 or higher)
• Coughing
• Congestion
• Sneezing
• Runny nose
• Decrease in appetite

After one or two days, the virus can travel to the lungs, affecting the small airways (called bronchioles) that allow your child to breathe easily. Once the airways are affected you may notice faster breathing, flaring of the nostrils, sinking of the neck and sucking in of the ribs while breathing. These are indicators that your child is having difficulties moving air into and out of the lungs and needs to be seen by a doctor.

Symptoms of bronchiolitis include:

• Faster breathing
• Flaring of the nostrils
• Sinking of the neck and sucking in of the ribs while breathing
• Rhythmic grunting during breathing
• Wheezing

How can I tell if my child has COVID-19, RSV or the flu?

COVID-19 has many similarities to the flu and RSV because they are all contagious respiratory viruses that spread from person to person by droplets traveling through the air. But there are key differences as well:

• Children with COVID-19 may not have symptoms at all, or may have a gradual onset of fever, congestion, cough and loss of taste and smell that last anywhere between seven to 28 days. Neither RSV nor the flu typically cause a loss of taste or smell, so if your child has these symptoms there’s a good chance they have COVID-19.
• Older children with RSV usually have minor symptoms similar to a cold. Younger kids and babies with RSV tend to have a slow onset of cold-like symptoms and then a sudden escalation. Symptoms last three to seven days.
• Most children who have the flu will experience a rapid onset of symptoms such as fever, cough and runny nose, and these symptoms will last from five to seven days.

To learn more about the differences between COVID-19, RSV and the flu, read our article: COVID-19 vs. RSV vs. flu: How to tell the difference.

How is respiratory syncytial virus treated?

Most RSV infections go away on their own in one or two weeks. While there is no specific treatment for RSV, some things you can do to relieve symptoms are:

1. Manage fever and pain with over the counter fever reducers and pain relievers such as acetaminophen or ibuprofen.
2. Keep your child hydrated. Make sure your child drinks a lot of fluids to prevent dehydration.

How do I prevent my child from catching respiratory syncytial virus?

Preventing RSV can be very difficult, especially because it is spread in droplets of fluid from sneezing, coughing or laughing. Since the virus travels and lives on surfaces, washing your hands often and keeping infants away from children and adults who are exhibiting common cold symptoms can be extremely helpful. Breastfeeding and avoiding second-hand smoke also show natural benefits to possibly preventing RSV.

Infants less than eight months old can receive Beyfortus to help prevent severe RSV illness.

Download our respiratory syncytial virus (RSV) infographic infographic here.