“RSV is a leading cause of morbidity and mortality worldwide in children aged under 5,” Francesca Knapper, MBBS, BSc, and colleagues wrote. “Children are predominately affected, with the greatest burden of disease in [children younger than 1]. … In adults, the burden of disease is less well understood.”

For a retrospective study published in The Pediatric Infectious Disease Journal, Knapper and colleagues examined all children and adults admitted for RSV during the 2019-2020 season across a large network of facilities with 669 inpatient beds, including 190 for children. All patients had standardized sample collection completed at the time of admission, including respiratory samples for virus isolation and bacterial and other relevant cultures depending on clinical presentation.

Incidence of Comorbidities & Factors Influencing Hospitalization

The analysis included 406 pediatric patients and 81 adult patients. In the pediatric cohort, there were slightly more boys (N=233) than girls (N=173). More than half of the children (52%) were aged younger than 12 months; much of the entire pediatric cohort (79%) was aged less than 2. Among adult patients, there were more females than males (56% vs 44%), and the average age was 67.

Almost all patients in the adult cohort (94%) had comorbidities, with COPD, cardiovascular disease, and cancer of a solid organ occurring the most frequently. Prematurity was the most common comorbidity in the
pediatric cohort, occurring in 9% of the group, followed by respiratory (8%), neurologic (4%), and cardiac (3%) abnormalities. Only a small minority of children (3%) had more than one comorbidity.

“In the pediatric cohort, the detection of RSV in association with other viruses was common,” the investigators wrote. “Rhinovirus was the next most frequently detected pathogen, found in 97 (24%) children, followed by adenovirus 24 (6%) and parainfluenza 22 (5%). … In the adult cohort, the majority had a limited respiratory panel with just RSV and [influenza]. No patients had coinfection with [influenza].”

While antibiotic use was higher in the adult cohort, the duration of hospital stay was “broadly similar,” Knapper and colleagues noted. “In the pediatric cohort, 169 (41%) were discharged within 48 hours compared
with 36 (44%) in the adult group,” they wrote. Just over half of the children in the pediatric cohort had a hospital stay of 3-7 days. Fewer adults (43%) had a hospital stay of that duration.

Approximately a tenth of the pediatric cohort (N=40) were admitted to the pediatric ICU (PICU); most of these patients (N=28) were aged younger than 6 months. Among children admitted to the PICU, 76% required
ventilation, and the mean duration of invasive ventilation was 3.5 days. A smaller percentage of adults (9%) were admitted to the ICU.

There were six deaths in the adult cohort and none in the pediatric cohort.

Clinicians ‘Should Not Underestimate’ the Burden of RSV

The findings indicate that RSV is associated with “significant morbidity,” according to Knapper and colleagues.

“Our data are in keeping with the current evidence that severe RSV affects those less than 6 months and that prematurity is significant risk factor,” the investigators wrote. “Comorbidities in adults also played an important role in hospitalization.”

The results demonstrate that all patients with an abnormal chest radiograph should undergo pneumococcal antigen testing and blood and sputum cultures. Knapper and colleagues noted that, while the results did not identify significant rates of coinfection, most children did not have sample testing done, and the pneumococcal antigen is not regularly utilized.

“With hopes of a vaccine some way off, improving management is essential,” they wrote. “While COVID-19 has taken the center stage, we should not underestimate the burden of RSV infection. More research to look at how we manage these patients and develop new therapeutic options is required.”