Respiratory Syncytial Virus (RSV): A Clinical Review (2026)

Respiratory syncytial virus (RSV) is a common but clinically significant viral infection that primarily affects the lower respiratory tract, especially in infants and young children. While most cases are mild and self-limited, RSV can lead to severe respiratory compromise in vulnerable populations such as premature infants and those with underlying cardiopulmonary disease.

It is a leading cause of bronchiolitis and a major contributor to pediatric hospitalizations worldwide. Understanding the pathophysiology, clinical presentation, and management of RSV is essential for respiratory therapists and other healthcare professionals.

What Is Respiratory Syncytial Virus (RSV)?

Respiratory syncytial virus (RSV) is a highly contagious viral infection that primarily affects the respiratory tract, especially in infants and young children. It is the leading cause of bronchiolitis and a common cause of pneumonia in children under 2 years of age.

RSV spreads through respiratory droplets and direct contact with infected secretions. The virus infects the epithelial cells of the airways, leading to inflammation, mucus production, and narrowing of the bronchioles. This results in symptoms such as coughing, wheezing, rapid breathing, and increased work of breathing.

While most cases are mild and resemble a common cold, RSV can cause severe respiratory distress in high-risk populations, including premature infants, those with chronic lung disease, and individuals with weakened immune systems.

Overview and Epidemiology

Respiratory syncytial virus is an enveloped RNA virus that belongs to the Paramyxoviridae family. It is highly contagious and spreads through respiratory droplets, direct contact with infected secretions, and contaminated surfaces. The virus can survive for several hours on surfaces, which contributes to its rapid transmission in community and healthcare settings.

RSV infections occur worldwide and follow a seasonal pattern, typically peaking during the winter months in temperate climates. Nearly all children are infected with RSV by the age of two. However, the severity of illness varies widely. While many children experience mild upper respiratory symptoms, others develop significant lower airway disease requiring hospitalization.

High-risk populations include:

• Premature infants
• Infants with bronchopulmonary dysplasia
• Children with congenital heart disease
• Patients with immunodeficiency
• Elderly individuals and adults with chronic lung disease

Note: In these groups, RSV can lead to severe complications, including respiratory failure and prolonged hospitalization.

Pathophysiology of RSV Infection

RSV primarily targets the epithelial cells lining the respiratory tract. Once the virus enters the body, it attaches to and infects these cells, leading to inflammation and cellular damage. The resulting pathophysiologic changes are most pronounced in the small airways, or bronchioles.

The infection triggers several key processes:

• Cellular necrosis and sloughing of epithelial cells
• Edema of the airway walls
• Increased mucus production
• Infiltration of inflammatory cells

These changes result in narrowing and obstruction of the bronchioles. In infants, this is especially problematic because their airways are already small. Even minor swelling or mucus accumulation can significantly increase airway resistance.

As airflow becomes obstructed, air trapping occurs. Air is able to enter the lungs during inspiration but cannot exit effectively during expiration. This leads to hyperinflation of the lungs. At the same time, complete obstruction in some airways can result in atelectasis, where portions of the lung collapse.

The combination of hyperinflation and atelectasis contributes to ventilation-perfusion mismatch. Some areas of the lung receive oxygen but are poorly perfused, while others are perfused but not adequately ventilated. This imbalance leads to hypoxemia.

Note: In more severe cases, increased work of breathing and respiratory muscle fatigue can impair ventilation, resulting in carbon dioxide retention and respiratory acidosis.

Clinical Presentation

RSV infection typically begins with symptoms of an upper respiratory infection before progressing to involve the lower airways. The progression usually occurs over several days.

Early Symptoms

The initial presentation is often mild and may include:

• Nasal congestion
• Rhinorrhea
• Low-grade fever
• Mild cough

Note: These symptoms may resemble a common cold, making early diagnosis challenging.

Progressive Lower Respiratory Symptoms

As the infection spreads to the bronchioles, more severe symptoms develop:

• Tachypnea
• Increased work of breathing
• Nasal flaring
• Intercostal and subcostal retractions
• Wheezing
• Crackles on auscultation

Note: Infants may also demonstrate poor feeding, irritability, and signs of dehydration. Because infants rely heavily on nasal breathing, congestion can significantly impair their ability to feed and maintain adequate hydration.

Severe Manifestations

In high-risk patients or severe cases, RSV can lead to:

• Hypoxemia
• Apnea, particularly in premature infants
• Respiratory fatigue
• Respiratory failure requiring ventilatory support

Note: The severity of illness ranges from mild, self-limited disease to life-threatening respiratory compromise. Careful monitoring is essential to identify patients who are at risk of deterioration.

Diagnostic Evaluation

The diagnosis of RSV is often clinical, particularly during peak seasonal outbreaks when the prevalence of the virus is high. However, laboratory testing may be used in certain situations, such as in hospitalized patients or for infection control purposes.

Laboratory Testing

Several diagnostic methods are available:

• Rapid antigen detection tests using immunofluorescence
• Enzyme-linked immunosorbent assay (ELISA) of nasal secretions
• Polymerase chain reaction (PCR) testing

Note: These tests are typically performed on nasal or nasopharyngeal specimens and can provide relatively quick confirmation of RSV infection.

Radiographic Findings

Chest radiographs are not routinely required but may be helpful in moderate to severe cases. Common findings include:

• Hyperinflation of the lungs
• Flattened diaphragms
• Patchy infiltrates
• Areas of atelectasis

Note: These findings reflect the underlying airway obstruction and air trapping associated with bronchiolitis.

Blood Gas Analysis

In more severe cases, arterial blood gas analysis may be necessary to assess gas exchange. Findings may include:

• Hypoxemia due to ventilation-perfusion mismatch
• Hypercapnia in cases of ventilatory failure
• Respiratory acidosis in advanced disease

Note: Monitoring these parameters helps guide clinical management and determine the need for respiratory support.

Management and Supportive Care

The management of RSV infection is primarily supportive. There is no universally recommended antiviral therapy for routine cases, so treatment focuses on maintaining adequate oxygenation, hydration, and airway patency.

Oxygen Therapy

Supplemental oxygen is provided to patients with hypoxemia. Oxygen may be delivered using:

• Nasal cannula
• Simple face mask
• High-flow nasal cannula in more severe cases

Note: The goal is to maintain adequate oxygen saturation while minimizing the work of breathing.

Hydration

Maintaining hydration is critical, especially in infants who may have difficulty feeding due to respiratory distress. Fluids may be administered:

• Orally, if the patient can tolerate feeds
• Intravenously, in cases of dehydration or poor oral intake

Note: Adequate hydration helps thin secretions and supports overall physiological function.

Airway Clearance

Airway clearance techniques may be used to help mobilize secretions. These include:

• Nasal suctioning
• Nasopharyngeal suctioning

Note: These interventions are particularly important in infants, who are obligate nasal breathers. Clearing nasal passages can significantly improve ventilation and feeding.

Escalation of Respiratory Support

In patients with moderate to severe respiratory distress, additional respiratory support may be required.

High-Flow Nasal Cannula

High-flow nasal cannula therapy delivers heated and humidified oxygen at higher flow rates. It can:

• Improve oxygenation
• Reduce work of breathing
• Provide a small amount of positive airway pressure

Note: This therapy is commonly used in pediatric patients with RSV bronchiolitis.

Continuous Positive Airway Pressure (CPAP)

CPAP may be used to maintain airway patency and improve gas exchange. It helps prevent airway collapse and reduces the effort required for breathing.

Mechanical Ventilation

In severe cases, mechanical ventilation may be necessary. Indications include:

• Severe hypoxemia despite supplemental oxygen
• Rising carbon dioxide levels
• Apnea
• Signs of respiratory fatigue or failure

Note: Patients requiring mechanical ventilation must be closely monitored for complications such as ventilator-associated lung injury and secondary infections.

Pharmacologic Therapy

Pharmacologic treatment in RSV infection is limited, and most interventions focus on supportive care rather than routine medication use. Several therapies have been studied, but few have demonstrated consistent clinical benefit in typical cases of RSV bronchiolitis.

Ribavirin

Ribavirin is an antiviral medication that has been approved for the treatment of RSV infection. It is delivered as a nebulized aerosol using a specialized small-particle aerosol generator (SPAG). The medication is administered continuously, often for 12 to 18 hours per day, over a course of several days.

Despite its availability, ribavirin is not routinely recommended for most patients. The reasons include:

• Limited evidence of significant clinical benefit
• High cost
• Complexity of administration
• Potential risks to healthcare providers due to aerosol exposure

Note: Ribavirin may be considered in severe, life-threatening cases, particularly in high-risk patients such as those who are immunocompromised or have significant underlying cardiopulmonary disease.

Bronchodilators

Bronchodilators such as albuterol are sometimes used in clinical practice, especially when wheezing is present. However, their routine use in RSV bronchiolitis is controversial.

Some patients may demonstrate a temporary improvement in symptoms, but studies have not consistently shown meaningful or sustained benefits. As a result, bronchodilators are not routinely recommended unless there is a clear and documented clinical response.

Corticosteroids

Corticosteroids have also been studied in the management of RSV infection. However, evidence does not support their routine use in typical cases of bronchiolitis.

They may be considered in select situations, such as in patients with underlying reactive airway disease, but they are not part of standard treatment for uncomplicated RSV infection.

Antibiotics

Antibiotics are not indicated in RSV infection because it is a viral illness. Their use should be reserved for cases where there is clear evidence of a secondary bacterial infection.

Unnecessary use of antibiotics should be avoided to prevent antimicrobial resistance and reduce the risk of adverse effects.

Prevention Strategies

Preventing RSV infection is a key component of reducing its clinical impact, particularly in high-risk populations.

Palivizumab Prophylaxis

Palivizumab is a monoclonal antibody directed against RSV. It is used as a preventive measure rather than a treatment.

Key features include:

• Administered as monthly intramuscular injections during RSV season
• Provides passive immunity against RSV
• Reduces the risk of severe disease and hospitalization

Indications for palivizumab include:

• Premature infants
• Infants with bronchopulmonary dysplasia
• Infants with significant congenital heart disease
• Children with certain airway abnormalities
• Immunocompromised patients

Note: It is important to emphasize that palivizumab does not treat active RSV infection. Its role is strictly prophylactic.

Infection Control Measures

Because RSV is highly contagious, infection control practices are essential in both community and healthcare settings.

Key measures include:

• Frequent hand hygiene
• Use of gloves and gowns when appropriate
• Avoiding close contact with infected individuals
• Cleaning and disinfecting contaminated surfaces

Note: In hospital settings, contact precautions are often implemented to prevent the spread of RSV, especially in neonatal and pediatric units.

Complications of RSV Infection

While many cases of RSV infection resolve without significant issues, complications can occur, particularly in high-risk populations.

Acute Complications

Severe RSV infection may lead to:

• Hypoxemia due to impaired gas exchange
• Respiratory failure requiring ventilatory support
• Apnea, especially in premature infants
• Dehydration due to poor feeding

Note: Respiratory failure is one of the most serious complications and may necessitate advanced respiratory support, including mechanical ventilation.

Secondary Infections

Although less common, secondary bacterial infections may occur. These can include:

• Bacterial pneumonia
• Otitis media

Note: These conditions require appropriate antibiotic therapy and careful clinical evaluation.

Long-Term Consequences

Some children who experience severe RSV infection may develop long-term respiratory issues, including:

• Recurrent wheezing
• Increased risk of asthma later in childhood

Note: The relationship between RSV and the development of chronic respiratory conditions is still being studied, but evidence suggests that early severe infection may contribute to long-term airway hyperreactivity.

Special Considerations in High-Risk Populations

Certain populations are more vulnerable to severe RSV infection and require closer monitoring and more aggressive management.

Premature Infants

Premature infants have underdeveloped lungs and immune systems, making them particularly susceptible to severe disease. They are also at higher risk for apnea and respiratory failure.

Patients with Chronic Lung Disease

Children with bronchopulmonary dysplasia or other chronic lung conditions have reduced pulmonary reserve. RSV infection can significantly worsen their respiratory status.

Congenital Heart Disease

Infants with congenital heart disease may have compromised cardiopulmonary function, which increases the risk of severe hypoxemia and poor outcomes.

Immunocompromised Patients

Patients with weakened immune systems may have prolonged viral shedding and more severe disease courses. They are also more likely to require hospitalization and advanced support.

Clinical Significance for Respiratory Therapists

Respiratory therapists play a critical role in the management of patients with RSV infection. Their responsibilities include:

• Assessing respiratory status and identifying signs of distress
• Administering oxygen therapy and monitoring oxygenation
• Performing airway clearance techniques
• Assisting with noninvasive and invasive ventilation
• Monitoring for complications and response to therapy

Early recognition of worsening respiratory status is essential. Prompt intervention can prevent progression to respiratory failure and improve patient outcomes.

In addition, respiratory therapists must adhere to infection control protocols to prevent the spread of RSV within healthcare facilities.

Respiratory Syncytial Virus (RSV) Practice Questions

1. What type of virus is respiratory syncytial virus (RSV)?
RSV is an enveloped RNA virus.

2. What age group is most commonly affected by RSV?
Infants and young children under 2 years of age.

3. What is the most common lower respiratory condition caused by RSV?
Bronchiolitis

4. What is the primary site of infection in RSV?
The epithelial cells lining the respiratory tract.

5. How is RSV most commonly transmitted?
Through respiratory droplets and direct contact with secretions.

6. During which season does RSV typically peak in temperate climates?
Winter months

7. What percentage of children are infected with RSV by age two?
Nearly all children.

8. What is the main pathophysiologic effect of RSV in the bronchioles?
Inflammation and obstruction.

9. What causes airway narrowing in RSV infection?
Edema, mucus production, and sloughed epithelial cells.

10. Why are infants more susceptible to severe RSV infection?
They have smaller airways that are easily obstructed.

11. What happens when air becomes trapped in the lungs during RSV infection?
Hyperinflation occurs.

12. What condition may develop due to complete airway obstruction in RSV?
Atelectasis

13. What type of gas exchange abnormality is common in RSV?
Ventilation-perfusion mismatch

14. What is a common early symptom of RSV infection?
Nasal congestion

15. What respiratory rate abnormality is seen in RSV?
Tachypnea

16. What physical sign indicates increased work of breathing in RSV?
Intercostal retractions

17. What abnormal lung sound is commonly heard in RSV?
Wheezing

18. What feeding-related issue is common in infants with RSV?
Poor feeding

19. What severe breathing event may occur in premature infants with RSV?
Apnea

20. What is the primary method of diagnosing RSV in most cases?
Clinical presentation

21. What type of test can rapidly detect RSV antigens?
Immunofluorescence assay

22. What imaging finding is commonly seen on chest X-ray in RSV?
Hyperinflation

23. What diaphragm change may be seen on chest X-ray in RSV?
Flattened diaphragms

24. What is the main goal of RSV treatment?
Supportive care

25. What is the first-line therapy for hypoxemia in RSV?
Supplemental oxygen

26. What is the primary goal of hydration in RSV management?
To maintain fluid balance and help thin secretions.

27. What airway clearance method is commonly used in infants with RSV?
Nasal suctioning

28. Why is nasal suctioning especially important in infants with RSV?
They are obligate nasal breathers.

29. What type of oxygen delivery system provides heated, humidified high flow?
High-flow nasal cannula

30. What is one benefit of high-flow nasal cannula therapy in RSV?
It reduces the work of breathing.

31. What type of pressure support does CPAP provide in RSV patients?
Continuous positive airway pressure to keep airways open.

32. What is an indication for mechanical ventilation in RSV?
Severe hypoxemia despite oxygen therapy.

33. What blood gas change indicates ventilatory failure in RSV?
Rising PaCO₂

34. What is ribavirin used for in RSV?
Treatment of severe or high-risk RSV infections.

35. How is ribavirin administered?
As a nebulized aerosol.

36. What device is used to deliver ribavirin?
A small-particle aerosol generator (SPAG).

37. How many hours per day is ribavirin typically administered?
12 to 18 hours per day

38. What is one major concern with ribavirin administration?
Exposure risk to healthcare providers.

39. Why is ribavirin not routinely used in RSV?
Limited benefit and high cost.

40. What class of medication is albuterol?
A bronchodilator.

41. Why are bronchodilators not routinely recommended in RSV?
They do not show consistent clinical benefit.

42. When might bronchodilators be considered in RSV?
If there is a clear clinical response.

43. Are corticosteroids routinely recommended for RSV bronchiolitis?
No, they are not.

44. What type of infection must be present to justify antibiotic use in RSV?
A secondary bacterial infection.

45. What type of medication is palivizumab?
A monoclonal antibody.

46. What is the purpose of palivizumab in RSV?
Prevention of severe infection.

47. How is palivizumab administered?
Monthly intramuscular injections.

48. Is palivizumab used to treat active RSV infection?
No, it is used for prophylaxis only.

49. What type of patients qualify for palivizumab prophylaxis?
High-risk infants such as premature or those with heart or lung disease.

50. What basic hygiene practice helps prevent RSV transmission?
Hand hygiene

51. What type of isolation precaution is recommended for hospitalized RSV patients?
Contact precautions

52. What is a common complication of RSV due to impaired gas exchange?
Hypoxemia

53. What serious outcome may require ventilatory support in RSV?
Respiratory failure

54. What is a common cause of dehydration in infants with RSV?
Poor feeding

55. What type of secondary ear infection can occur with RSV?
Otitis media

56. What type of lung infection can develop as a secondary complication of RSV?
Bacterial pneumonia

57. What long-term respiratory symptom may follow severe RSV infection?
Recurrent wheezing

58. What chronic respiratory condition has been linked to severe RSV in infancy?
Asthma

59. Why are premature infants at higher risk for severe RSV?
They have immature lungs and immune systems.

60. What chronic lung condition increases RSV severity risk in infants?
Bronchopulmonary dysplasia

61. How does congenital heart disease affect RSV outcomes?
It increases the risk of severe hypoxemia.

62. Why are immunocompromised patients more vulnerable to RSV?
They have a reduced ability to fight the infection.

63. What is a key responsibility of respiratory therapists in RSV care?
Monitoring respiratory status.

64. What sign indicates worsening respiratory distress in RSV?
Increased work of breathing.

65. What intervention helps reduce airway resistance in RSV infants?
Clearing nasal secretions.

66. What type of respiratory support may be used before intubation in RSV?
Noninvasive ventilation

67. What clinical sign may indicate fatigue in RSV patients?
Decreased respiratory effort.

68. What is the role of humidification in RSV management?
To help loosen secretions.

69. What type of breathing phase is often prolonged in RSV?
Expiration

70. What auscultation finding indicates mucus in the airways?
Crackles

71. What happens to airway resistance during RSV infection?
It increases.

72. What is the primary cause of wheezing in RSV?
Airflow obstruction in the bronchioles.

73. What happens to ventilation in areas affected by atelectasis?
It decreases or is absent.

74. What is a common behavioral sign of distress in infants with RSV?
Irritability

75. What monitoring tool is essential for assessing oxygenation in RSV?
Pulse oximetry

76. What type of airway is primarily affected in RSV infection?
The small airways, or bronchioles.

77. What happens to epithelial cells during RSV infection?
They become damaged and slough off.

78. What contributes to mucus plugging in RSV?
Increased mucus production and cellular debris.

79. What is the effect of airway edema in RSV?
It narrows the airway lumen.

80. What type of mismatch occurs due to uneven ventilation in RSV?
Ventilation-perfusion mismatch

81. What happens to oxygen levels when V/Q mismatch occurs in RSV?
They decrease, leading to hypoxemia.

82. What type of breathing pattern is often seen in infants with RSV?
Rapid, shallow breathing.

83. What is a common nasal sign of respiratory distress in RSV?
Nasal flaring

84. What type of chest movement indicates labored breathing in RSV?
Subcostal retractions

85. What type of secretion buildup is common in RSV?
Thick mucus secretions

86. What clinical sign may indicate worsening hypoxemia in RSV?
Cyanosis

87. What type of fever is typically associated with RSV?
Low-grade fever

88. What happens to lung volumes during hyperinflation in RSV?
They increase.

89. What is the result of incomplete exhalation in RSV?
Air trapping

90. What is a common auscultation finding in early RSV infection?
Mild crackles

91. What happens to carbon dioxide levels in advanced RSV cases?
They increase.

92. What is a sign that a patient may be developing respiratory acidosis?
Elevated PaCO₂.

93. What type of respiratory support helps maintain alveolar recruitment?
CPAP

94. What type of patient positioning may help improve breathing in RSV?
Upright positioning

95. What is the effect of fatigue on ventilation in RSV patients?
It reduces effective ventilation.

96. What type of intervention can help reduce airway obstruction in RSV?
Airway suctioning

97. What is the significance of prolonged expiration in RSV?
It indicates airflow limitation.

98. What type of abnormal breath sound may indicate airway narrowing?
Wheezing

99. What is the role of monitoring in RSV management?
To detect deterioration early.

100. What is the overall treatment approach for most RSV cases?
Supportive care

Final Thoughts

Respiratory syncytial virus (RSV) is a highly prevalent and clinically important pathogen that primarily affects infants and young children. While most cases are mild, the virus can cause significant lower respiratory tract disease, particularly in vulnerable populations.

The pathophysiology involves inflammation and obstruction of the small airways, leading to impaired gas exchange and respiratory distress. Management is largely supportive, focusing on oxygenation, hydration, and airway clearance, with limited roles for pharmacologic therapy.

Preventive strategies, including palivizumab prophylaxis and infection control measures, are essential for reducing disease burden and improving outcomes in high-risk patients.