RSV Testing Age Cutoff
Routine RSV testing is generally not recommended beyond 2 years of age in otherwise healthy children, as the vast majority of severe RSV disease and hospitalizations occur in the first year of life, with less than 20% of pediatric RSV hospitalizations occurring during the second year. 1
Age-Specific Disease Burden
The epidemiology of RSV clearly demonstrates an age-related decline in severity:
- 75% of all pediatric RSV hospitalizations occur in infants under 12 months of age 1, 2
- Less than 20% occur during the second year of life (12-24 months) 1, 2
- RSV hospitalization rates decline significantly after the first year 1, 2
- By 2 years of age, most children will have had an RSV infection 3
Clinical Context for Testing Decisions
Routine RSV testing is not recommended for most children with respiratory illness, regardless of age, because management is primarily supportive. 4 The key consideration is whether identifying RSV will change clinical management:
When RSV Testing May Be Indicated (Any Age):
- High-risk populations requiring risk stratification (immunocompromised, transplant recipients, severe underlying cardiopulmonary disease) 5, 1
- Infants receiving palivizumab prophylaxis who develop bronchiolitis - testing determines if breakthrough RSV infection occurred, which would warrant discontinuation of further prophylaxis 5
- Hospitalized patients for infection control purposes 1
- Febrile infants ≤60 days old being evaluated for serious bacterial infection - positive RSV reduces (but does not eliminate) risk of concurrent bacterial infection 5
When RSV Testing Is NOT Recommended:
- Well-appearing children >2 years with typical upper respiratory symptoms 4
- Routine outpatient bronchiolitis cases where management will be supportive regardless 5
- When respiratory virus testing is performed, prioritize influenza and COVID-19 testing first as these have specific antiviral treatments available 4
Special Populations Beyond Age 2
Children >24-59 months with significant comorbidities (neuromuscular disorders, chronic lung disease, reactive airway disease/asthma) remain at risk for severe RSV disease and may warrant testing if hospitalized. 6 In one large cohort study, 14.8% of RSV hospitalizations occurred in children 24-59 months, with 70% having underlying comorbidities. 6
Common Pitfall to Avoid
Do not confuse the age cutoff for routine testing (approximately 2 years) with the age cutoff for immunoprophylaxis eligibility. Nirsevimab is recommended for all infants <8 months entering their first RSV season, and for high-risk children 8-19 months entering their second season. 7 Testing and prevention strategies have different age thresholds based on different clinical rationales.