How does respiratory syncytial virus present in an otherwise healthy immunocompetent adult?

RSV Presentation in Immunocompetent Adults

In otherwise healthy immunocompetent adults, RSV typically presents as an upper respiratory tract infection with prominent nasal discharge/congestion, cough, and rhinorrhea, though it can progress to lower respiratory tract disease with dyspnea and wheezing in a substantial proportion of cases. 1, 2

Primary Clinical Features

Upper Respiratory Symptoms

• Cough is the most common symptom, occurring in approximately 93% of adult RSV cases, often persistent and productive 2
• Nasal discharge and congestion are hallmark features, frequently severe and distinguishing RSV from typical viral upper respiratory infections 3, 4
• Rhinorrhea tends to be profuse and prolonged, lasting well beyond typical cold symptoms 4
• Pharyngeal pain may be the initial presenting symptom before other respiratory manifestations develop 4

Lower Respiratory Manifestations

• Dyspnea occurs in approximately 91% of hospitalized adult RSV cases, indicating frequent lower respiratory tract involvement even in immunocompetent hosts 2
• Wheezing is present in approximately 74% of cases, a distinctive feature that helps differentiate RSV from other respiratory viral infections 2
• Sputum production occurs in 87% of cases, often copious and requiring symptomatic management 2
• Tachypnea develops in approximately 75% of hospitalized patients, reflecting the respiratory burden of infection 2

Systemic Symptoms

• Fever occurs in approximately 71% of adult RSV cases, though it may be absent or low-grade in many immunocompetent adults 2
• In some immunocompetent adults, body temperature may not exceed 37°C despite active infection, with only slight chills reported 4
• The illness tends to be more severe than the average cold and may present with influenza-like manifestations 5

Disease Progression and Timeline

Typical Course

• Symptoms typically peak at approximately 5-7 days after onset and can persist for 12 days or longer 4
• The initial presentation often begins with pharyngeal symptoms, followed by progressive development of nasal and lower respiratory manifestations 4
• RSV symptoms can last for weeks and show considerable variability based on individual factors and geography 3

Secondary Complications

• Acute sinusitis can develop as a secondary complication, typically appearing around day 9 of illness with dull headache or facial pain 4
• Sinusitis may persist for at least a week after onset and can be confirmed by imaging studies 4
• The headache associated with secondary sinusitis is characteristically dull and localized to the maxillary or frontal regions 4

Diagnostic Considerations

Clinical Recognition Challenges

• RSV often goes unrecognized in adults unless highly sensitive molecular diagnostic tests are used, leading to underdiagnosis in this population 1
• Chest radiographs are often normal despite significant lower respiratory symptoms and hypoxia, making clinical diagnosis challenging 1
• Hypoxemia (SpO2 ≤92%) can occur in approximately 54% of cases, even when radiographic findings are minimal 2

Laboratory Findings

• Routine clinical laboratory examinations typically show minimal abnormalities, with only slight increases in serum C-reactive protein levels 4
• RT-PCR is the most sensitive diagnostic method, detecting RSV in approximately 83% of confirmed cases 2
• Immunofluorescence assay (IFA) has lower sensitivity but can provide rapid results in approximately 10% of cases 2

Important Clinical Caveats

• All RSV infections in adults represent reinfection since immunity is neither complete nor durable, with repeated infections occurring throughout life 1
• While most cases in healthy adults involve the upper respiratory tract, a substantial proportion progress to lower respiratory tract disease requiring medical attention 1, 2
• The severity of illness in immunocompetent adults is generally underappreciated, with symptoms often more severe than typical viral upper respiratory infections and resulting in work absence 5
• Even in immunocompetent adults without traditional risk factors, RSV can cause significant respiratory compromise requiring careful monitoring 2