What are the most common viruses associated with rhinorrhea in children under 5?

Most Common Viruses Causing Rhinorrhea in Children Under 5

The five most common viruses associated with rhinorrhea in children under 5 years are: (1) Respiratory Syncytial Virus (RSV), (2) Rhinoviruses, (3) Human Coronaviruses (229E, NL63, OC43, HKU1), (4) Parainfluenza viruses, and (5) Human Metapneumovirus.

Primary Viral Pathogens

1. Respiratory Syncytial Virus (RSV)

• RSV is consistently the most frequently detected pathogen in children under 5 years, representing up to 40% of identified viral pathogens in those younger than 2 years 1
• RSV infects approximately 90% of children within the first 2 years of life, with initial presentation typically including 2-4 days of upper respiratory symptoms with clear, watery rhinorrhea before potential progression to lower respiratory involvement 2
• RSV demonstrates clear seasonal patterns with peak incidence between December and March in North America 2
• The CDC identifies RSV as the most common cause of lower respiratory tract infection in children under 2 years 2

2. Rhinoviruses

• Rhinoviruses are the second most frequently recovered pathogen, accounting for approximately 12-24% of acute respiratory infections in hospitalized children under 5 years 3, 4
• In older children (ages 1-2 years), rhinoviruses account for 65% of respiratory infections, and in children ≥3 years, they dominate at 82% 4
• Rhinoviruses are a major cause of lower respiratory tract infections in hospitalized children ≤3 years old, not just upper respiratory symptoms 3

3. Human Coronaviruses

• Four endemic human coronaviruses (229E, NL63, OC43, and HKU1) are associated with common cold symptoms including rhinorrhea, congestion, sore throat, sneezing, and cough 5
• In children, these coronaviruses also cause exacerbation of asthma and otitis media 5
• These viruses are now commonly detected in commercial respiratory panels using nucleic acid amplification tests 5

4. Parainfluenza Viruses

• Parainfluenza viruses are a major cause of upper respiratory tract infections in addition to croup, bronchiolitis, and pneumonia 5
• Parainfluenza virus infections account for up to 11% of all hospitalizations in children <5 years old 5
• Four antigenically distinct types exist, with types 1 and 2 most commonly associated with croup syndrome, while type 3 is associated with bronchiolitis and pneumonia 5

5. Human Metapneumovirus

• Human metapneumovirus causes acute respiratory tract disease in people of all ages, with upper respiratory infections including rhinorrhea being common presentations in children 5
• The virus is associated with bronchiolitis in infants, pneumonia, asthma exacerbations, croup, and upper respiratory infections with concomitant otitis media 5
• Most commonly, children present with mild to moderate symptoms 5
• Human metapneumovirus was detected in 4% of all children with acute expiratory wheezing and in 11% of infants 4

Additional Notable Viral Pathogens

• Enteroviruses account for approximately 25% of acute expiratory wheezing cases in children, particularly in infants where they represent 42% of cases 4
• Influenza viruses (types A and B) represent approximately 4% of lower respiratory tract infections in hospitalized children under 5 years 6
• Adenoviruses account for approximately 3.4% of lower respiratory tract infections in this age group 6

Clinical Context and Diagnostic Considerations

• Multiple pathogen detection is extremely common, with 2-33% of hospitalized children with respiratory infections simultaneously infected by 2 or more viruses 1
• Viral etiologies have been documented in up to 80% of children younger than 2 years with community-acquired pneumonia 1
• The clinical presentation of rhinorrhea is indistinguishable between these viral etiologies, making specific viral diagnosis based on symptoms alone impossible 2
• Routine viral testing is not necessary for typical cases as it does not change management in most clinical scenarios 7