The study found that other signs of respiratory distress, such as low arterial blood oxygen or rapid shallow breathing, were no more common in severely premature children (less than 32 weeks of gestational age) than in kids born preterm or full-term. The findings have implications for administering supportive care sooner or more intensively for severely premature children than for other infants.

The study team sought to identify clinical phenotypes of Human rhinovirus (HRV) infections in young children hospitalized for such infections. The team theorized that severely premature babies would respond differently to these infections and that their response might resemble symptoms experienced by patients with asthma. The study was published in Pediatrics and Neonatology,

"For a number of years, our team has studied responses to viruses and prematurity, especially HRV and asthma," the study lead author Dr. Geovanny Perez said. "We know that premature babies have an immune response to HRV from the epithelial cells, similar to that seen in older patients with asthma. But we wanted to address a gap in the research to better understand which children may need closer monitoring and more supportive care during their first HRV infection."

In a retrospective cross-sectional analysis, the study looked at 205 children aged 3 years or younger who were hospitalized at Children's National in 2014 with confirmed HRV infections. Of these, 71% were born full-term (more than 37 gestational weeks), 10% were preterm (32 to 37 gestational weeks) and 19% were severely premature (less than 32 gestational weeks).

Dr. Perez and his team developed a special respiratory distress scoring system based on physical findings in the children's electronic medical records to assess the degree of lower-airway obstruction or AHR and of parenchymal lung disease. The physical findings included:

  1. Wheezing;
  2. Subcostal as can occur in pneumonia;
  3. Reduced oxygen levels and
  4. Increased respiratory rate.

The research team assigned each case an overall score. The severely premature children had worse overall scores and significantly worse scores for AHR and hyperinflated lungs relative to children born late preterm or full-term.

"What surprised us, though, in this study was that the phenotypical characterization using individual parameters for parenchymal lung disease, such as hypoxemia or tachypnea, were not different in severe preterm children and preterm or full term," says Dr. Perez.

"On the other hand, our study found that severely preterm children had a lower airway obstruction phenotype associated with retractions and wheezing. Moreover there was a 'dose effect' of prematurity: Children who were born more premature had a higher risk of wheezing and retractions."

Among the implications of this study, Dr. Perez sees the potential to use phenotypical and biological biomarkers to better personalize patients' treatments. Dr. Perez and his team have identified biological biomarkers in nasal secretions of children with rhinovirus infection that they plan to combine with clinical biomarkers to identify which patients with viral infections will benefit from early supportive care, chronic treatments or long-term monitoring.