What is Respiratory Syncytial Virus (RSV)?
Respiratory syncytial (sin-SISH-uhl) virus, or RSV, is a type of common respiratory virus which causes mild, flu-like symptoms such as coughing, sneezing, wheezing, fever, runny nose, and decrease in appetite.
Infants/young children and older adults are most at risk for severe disease that may require hospitalization. RSV can also cause severe symptoms in people with weakened immune systems or chronic heart and lung diseases.
Within the United States, RSV is the most common cause of bronchiolitis (inflammation of the small airways of the lung) or pneumonia (infection of the lungs) in children younger than one year.
RSV is a common respiratory virus that usually causes mild, cold-like symptoms such as:
• Runny nose
• Decrease in appetite
People infected with RSV usually show symptoms within 4 to 6 days after getting infected. Symptoms usually appear in stages and not all at once.
In very young infants with RSV, the only symptoms may be irritability, decreased activity, and breathing difficulties.
Who gets RSV?
Virtually all children get an RSV infection by the time they are 2 years old. However, anyone can get an RSV infection at any age and you can become infected more than once in your lifetime. Infants, young children, and older adults are more likely to get serious complications if they get sick with RSV.
People at high risk for severe RSV
People at greatest risk for severe illness from RSV include:
• Premature infants
• Infants (especially those 6 months and younger)
• Children younger than 2 years old with chronic lung disease or congenital (present from birth) heart disease
• Children with weakened immune systems
• Children who have neuromuscular disorders, including those who have difficulty swallowing or clearing mucus secretions
Call your healthcare provider if your child is having difficulty breathing, not drinking enough fluids, or experiencing worsening symptoms.
Adults at highest risk for severe RSV infection include:
• Older adults (especially those 65 years and older)
• Adults with chronic heart or lung disease
• Adults with weakened immune systems
Children are often exposed to and infected with RSV outside the home, such as in school or childcare centers. They can then transmit the virus to other members of the family.
RSV can spread when:
• An infected person coughs or sneezes
• You get virus droplets from a cough or sneeze in your eyes, nose, or mouth
• You have direct contact with the virus, such as kissing the face of a child with RSV
• You touch a surface that has the virus on it and then touch your face before washing your hands
RSV can survive for many hours on hard surfaces such as tables and crib rails. It typically lives on soft surfaces such as tissues and hands for shorter amounts of time.
People infected with RSV are usually contagious for 3 to 8 days and may become contagious a day or two before showing signs of illness. However, some infants, and people with weakened immune systems, can continue to spread the virus even after they stop showing symptoms (for as long as 4 weeks).
A healthcare provider may suspect RSV based on medical history, time of year, and a physical exam. A mouth swab or blood test to check white blood cell counts and look for viruses may be performed.
In severe RSV cases that require hospitalization, additional testing may be needed.
Most RSV infections go away on their own in a week or two. There is no specific treatment, but researchers are working to develop vaccines and antivirals (medicines that fight viruses). Antibiotics will not cure RSV infections because antibiotics only kill bacteria, not viruses.
You can protect yourself and others from RSV, and other respiratory illnesses, by following a few simple steps:
• Wash hands often
• Keep hands off your face
• Avoid close contact with sick people
• Cover coughs and sneezes
• Clean and disinfect surfaces
• Stay home when sick
RSV FAQ > [PDF]
RSV Factsheet for Infants and Young Children [CDC]
RSV Factsheet for Older Adults [CDC]
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Last Updated January 6, 2023