Human Metapneumovirus and Respiratory Syncytial Virus in Children: A Comparative Analysis

Abstract

Background: Human metapneumovirus (HMPV) and respiratory syncytial virus (RSV) are genetically related viruses and major causes of medically attended acute respiratory illness in children. Research comparing the severity of illnesses resulting from these infections lacks consensus.

Methods: Children younger than 18 years with acute respiratory illness were enrolled through active, prospective surveillance from 2016 to 2020 at 7 US pediatric hospitals and emergency departments (EDs). Clinical information was obtained from parent interviews and medical records. Midturbinate nasal swabs were collected and tested for RSV and HMPV using molecular diagnostic assays at each site. We compared descriptive and clinical features of children with RSV or HMPV and calculated adjusted odds ratios (aOR) for severe outcomes comparing RSV with HMPV. Risk factors for severe outcomes were assessed in children with RSV or HMPV using logistic regression models.

Results: A total of 5329 children hospitalized with RSV (n = 4398) or HMPV (n = 931) and 3276 children with RSV-associated (n = 2371) or HMPV-associated (n = 905) ED visits were enrolled. The median age of children hospitalized with RSV was lower than that of children with HMPV (7 months vs 16 months, P < .0001). Children presenting to the ED with RSV-associated acute respiratory illness had higher odds of being hospitalized than children with HMPV (aOR, 1.68; 95% CI, 1.50-1.87), with the highest odds in infants younger than 6 months (aOR, 3.27; 95% CI, 2.53-4.23). Underlying conditions were more than twice as common among infants hospitalized with HMPV (26%) than those with RSV (11%).

Conclusions: Children with HMPV-associated hospitalization tend to be older and more likely to have underlying medical conditions compared with children with RSV-associated hospitalization.

FIGURE 1.

Age distribution of children younger than 18 years with RSV- or HMPV-associated emergency department visits and hospitalizations, New Vaccine Surveillance Network, December 2016 to March 2020. HMPV, human metapneumovirus; RSV, respiratory syncytial virus.

FIGURE 2.

Percentage of viral polymerase chain reaction tests positive^a for RSV and HMPV among children younger than 18 years with acute respiratory illness–associated emergency department visits and hospitalizations, overall and by site, New Vaccine Surveillance Network, December 2016 to March 2020. ^a3-week moving average. HMPV, human metapneumovirus; RSV, respiratory syncytial virus.

FIGURE 3.

Risk factors for hospitalization, ICU admission, and length of stay of 3 or more days among children younger than 18 years with RSV or HMPV, New Vaccine Surveillance Network, December 2016 to March 2020. ^aUnique multivariable logistic regression models were used for each outcome OR. All models adjusted for study site and age in months. Age group analysis also adjusted for any underlying condition. ^bCompared with younger than 6 months. ^cCompared with non-Hispanic white. ^dCardiovascular disease, heart defect, other heart disease. ^eChronic lung condition, bronchopulmonary dysplasia, cystic fibrosis, airway disorders, sleep apnea, or other lung disease. ^fDevelopmental disorders, genetic/metabolic conditions, Down syndrome, other genetic conditions, and other developmental disabilities. ^gLiver diseases, chronic gastrointestinal disease, and gastroesophageal reflux disease. ^hDevelopmental disorders, genetic/metabolic conditions, Down syndrome, other genetic conditions, and other developmental disabilities. ⁱPrematurity defined as birth at less than 37 weeks’ gestation. ^jHigh school or less. ^kChild lives with someone who smokes tobacco products or electronic cigarettes. aOR, adjusted odds ratio; HMPV, human metapneumovirus; ICU, intensive care unit; OR, odds ratio; RSV, respiratory syncytial virus.