Preterm Infants More Likely to Be Hospitalized for RSV-Related Disease

In preterm infants, the rate of respiratory syncytial virus (RSV)-related acute lower respiratory infections (ALRIs) is disproportionately high, with preterm infants making up 25% of infants with RSV-related hospitalizations. These were among the findings of a systematic review and meta-analysis published in The Lancet.

Researchers sought to evaluate RSV-associated ALRI global disease burden and risk factors among infants and young children born preterm (before 37 weeks gestation).

The researchers conducted a systematic review and meta-analysis for studies reporting RSV-associated mortality and morbidity estimates among children born prematurely who were less than 2 years of age. In addition to searching the MEDLINE, Embase, and Global Health databases without language restriction from January 1995 through December 2021, the researchers invited the lead investigators of eligible studies and investigators within the Respiratory Virus Global Epidemiology Network to contribute individual participant data.

The researchers included 47 studies from the data search and 17 studies contributed by the participating investigators with individual-level participant data (N=42,374 participants; 3 studies from low- and lower-middle-income countries). RSV-associated ALRI was defined as physician-confirmed pneumonia or bronchiolitis with laboratory-confirmed RSV infection. Early preterm birth was defined as birth prior to 32 weeks gestation, and late preterm birth as birth at 32 to 37 weeks gestation.

The researchers estimated that among preterm infants worldwide in 2019, there were 3050 RSV-associated in-hospital deaths (95% uncertainty range [UR], 1080-8620); 26,760 RSV-attributed deaths overall (95% UR, 11,190-46,240), as well as 533,000 RSV-associated hospital admissions (95% UR, 385,000-730,000), and 1,650,000 RSV-associated ALRI episodes (95% UR, 1,350,000-1,990,000).

Incidence rates of RSV-associated ALRI in this patient population decreased in developing and industrialized counties between 2000 and 2019. About 93% of all episodes of RSV-associated ALRI in 2019 occurred in developing countries (data from 4 studies; I²=0.0), as well as about 92% of all RSV-associated ALRI hospitalizations (data from 10 studies; I²=82.4).

Overall, 25% (95% UR, 16-37) of RSV-associated ALRI hospitalizations in all infants of any gestational age were accounted for by preterm infants. The RSV-associated hospitalization rate and incidence rate were significantly higher among early preterm infants vs infants born at any gestational age (rate ratio [RR] range, 1.69-3.87 across age groups and various outcomes). Early preterm infants in the second year of life and young children vs all infants and young children had a significantly higher hospitalization rate (RR, 2.26; 95% UR, 1.27-3.98) although a similar incidence rate.

The investigators noted late-preterm infants vs all infants younger than 1 year had a higher RSV-associated ALRI hospitalization rate in the first 6 months (RR, 1.93; 95% UR, 1.11-3.26), although RSV-associated ALRI incidence rates were similar.

Preterm-infants vs all infants were similar with respect to RSV-associated ALRI in-hospital case mortality ratio.

Sociodemographic and perinatal characteristics were the primary factors associated with RSV-associated ALRI incidence. Underlying medical conditions (Down syndrome, chronic lung disease, bronchopulmonary dysplasia, tracheostomy, congenital heart disease) were the main factors associated with severe outcome from infection.

Systematic review and meta-analysis limitations include significant heterogeneity, misclassification bias (only 6 studies confirmed gestational age through ultrasound), and a lack of data from several global geographical regions (Africa, eastern Europe, central Asia, eastern Mediterranean).

“Preterm infants face a disproportionately high burden of RSV-associated disease, accounting for 25% of RSV hospitalization burden,” the investigators concluded. The review authors added, “Early preterm infants have a substantial RSV hospitalization burden persisting into the second year of life.”

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.

This article originally appeared on Pulmonology Advisor