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Respiratory Syncytial Virus (RSV)

Respiratory syncytial virus (RSV) is a very common cause of respiratory tract infection especially in young children. RSV is a member of the Paramyxoviridae family of viruses. There are two types of RSV, type A and B and there are many strains. RSV has an RNA genome that encodes 10 viral proteins. The virus has a lipid envelope that contains viral glycoproteins that are involved in entry of the virus into cells and fusion of the viral envelope with cell membranes. Much of the pathology caused by RSV is related to damage of the lining of the small airways of the respiratory tract.

RSV infection

RSV is a very common virus infection that often resembles the common cold with mild symptoms such as a runny nose, coughing and low-grade fever. However, symptoms indicative of more severe RSV infections may include difficult or rapid breathing, wheezing, irritability and restlessness, and poor appetite. RSV is readily spread from contact with respiratory secretions from infected individuals or contaminated surfaces and objects. The incubation period of RSV infection ranges from 2-8 days and most children recover from illness in about 8-15 days. Half of all infants become infected during their first year of life, while virtually all have been infected by the age of two.

RSV infections can occur any time of year, but most infections occur from October through April. In the United States, RSV is estimated to be responsible for 73,400 to 126,300 hospitalizations annually for bronchiolitis and pneumonia alone among children younger than one year. It is one of the most common viral causes of death in children younger than five years, particularly in children younger than one year. It is also the major viral cause of hospital-acquired infection. Children at the greatest risk of severe RSV infections include:

  • Infants born prematurely
  • Term infants younger than 6 weeks old
  • Children with medical conditions such as:
    • Chronic lung disease
    • Serious heart conditions
    • Problems with their immune system

Immunocompromised adults (cancer and bone marrow transplant patients, etc.) are very susceptible to severe RSV pneumonia. Elderly patients in long-term care facilities are also prone to RSV infection.


Clinicians are not able to accurately diagnose RSV infection based on signs and symptoms alone. There are many other viruses that infect the respiratory tract and there is a large overlap of symptoms among these infections. Diagnostic tests performed on specimens taken from the respiratory tract provide a useful aid to the diagnosis of RSV. There are a number of methods available to laboratories to detect RSV in respiratory specimens from patients. Traditionally, laboratories used viral culture to detect influenza virus and improvements in virus culture techniques allowed for results within 48-72 hours. The direct fluorescent antibody (DFA) method allows detection of virus within 2-3 hours, but is labor intensive and requires considerable experience. Molecular methods such as reverse transcription polymerase chain reaction (RT-PCR) based tests are the most accurate methods to detect RSV, but are expensive and can only be done in laboratories that can afford expensive equipment and employ highly trained technologists. Rapid antigen diagnostic test (RADTs), such as lateral flow tests, can be performed at the site of patient care such as the physicians’ office or emergency department. These tests offer the possibility of identifying an infected patient early in the course of the disease and during the patient’s visit to the health care facility.  Early diagnosis at the point-of-care can have a positive impact on clinical management decisions.

Medical management of RSV infection

Management of an RSV infection is generally focused on symptomatic therapy. When an RSV infection becomes more serious and progresses to bronchiolitis, patient management goals are to relieve respiratory distress, alleviate airway obstruction and improve oxygen levels. It is important to normalize body temperature and maintain proper hydration. Treatment with the antiviral ribavirin is reserved for seriously ill patients and has limited efficacy.

Prevention of RSV infection

There is no vaccine for available for RSV. Prevention of RSV infection depends on the behavior of child care providers and health care providers to reduce the spread of RSV. These efforts should include:

  • Wash hands frequently.
  • Avoid contact of children with individuals with cold-like illness.
  • Do not share personal items such as pacifiers, utensils, toothbrushes, and bed and bath linens among children.
  • Clean toys and play areas frequently.
  • Keep young children away from cigarette smoke.
  • Isolate hospitalized RSV-infected children

Recommended Reading

Collins P., Chanock R., Murphy B. Fields Virology. Fourth Edition. Volume 1. Chapter 45 - Respiratory Syncytial Virus. Lippincot Williams and Wilkins. (2001)

Thompson, W. et al. Mortality Associated With the Influenza and Respiratory Syncytial Virus in the United States. JAMA, January 8, 2003 - Vol 289, No. 2.

Respiratory Syncytial Virus (RSV). American Academy of Pediatrics http://www.healthychildren.org/English/health-issues/conditions/chest-lungs/Pages/Respiratory-Syncytial-Virus-RSV.aspx