Respiratory Syncytial Virus Associated Hospitalizations in Infants of 33 to 42 Weeksʼ Gestation: Does Gestational Age Matter?

Abstract

Background To evaluate rates and characteristics of respiratory syncytial virus hospitalizations (RSV-H) in infants of 33 to 42 weeks of gestational age (GA). Patients All infants with a history of neonatal hospitalization and a GA of 33 to 42 weeks born between 2005 and 2015 and follow-up at least over one RSV season (first year of life). Infants with congenital heart disease and other congenital anomalies were excluded. Methods Retrospective single-center cohort STROBE compliant study. Data were collected regarding demographic data and re-hospitalization characteristics due to respiratory illness and due to RSV infection; and data were compared between moderate-late preterm, near term, term, and post term infants, respectively. Results A total of 81.656 live born infants were registered in our catchment area with gestational age from 33 to 42 weeks during the study period; and 2188 of 2356 preterm infants and 1004 of 1168 term infants with history of neonatal hospitalization were included for analysis. Rehospitalizations due to respiratory illness occurred in 301 preterm (13.8%) and 136 term (13.5%) infants for 381 and 183 times, respectively. In total 84 of 3192 infants (2.6%) were tested RSV positive, 61 of 2188 preterm (2.8%) and 23 of 1004 term (2.3%). Preterm infants without history of neonatal hospitalization had a RSV hospitalization (RSV-H) rate of 1.7% (61/3488) and term infants of 1.3% (967/74.644) that were significantly lower compared to study infants (p=0.004 and 0.002, respectively). Moderate and late preterm (2.8%), near term (3.1%) and post term (3.5%) infants had significantly higher RSV-H rates compared to term infants (1.2%). Risk factors for RSV-H in preterm infants included discharge during RSV season (4.2 vs. 2.0%, p=0.017) and presence of older siblings (4.2 vs. 2.1%, p=0.023), in term infants presence of older siblings (p=0.019). The course of RSV disease did not differ between groups. Discussion Interestingly, we did not observe decreasing RSV-H rates with increasing GA. Term infants represented the group with lowest RSV-H rates. Neonatal hospitalization was a risk factor for RSV-H for both preterm and term infants. Near term infants do more resemble the late preterm than term infants regarding RSV-H rates. Conclusion We found comparable higher RSV-H rates in all groups compared to term infants without differences in the course of disease and identified neonatal hospitalization as an independent risk factor.

Modifiable environmental factors predispose term infants to bronchiolitis but bronchiolitis itself predisposes to respiratory sequelae

“…The BROME cohort constituted a homogeneous group of previously healthy full‐term infants admitted to the same hospital, 93% were <6 months and for all of them it was their first episode of lower respiratory infection 18 . The role of prematurity as a risk factor for bronchiolitis has already largely been demonstrated 21,22 ; thus, we interpreted our results as an impact of slightly lower gestational age even in a group of full‐term infants, on airway development that somehow predisposes to respiratory infections, as data in literature confirmed 23–25 …”

Prevalence and Risk Factors of Respiratory Syncytial Virus in Children under 5 Years of Age in the WHO European Region: A Systematic Review and Meta-Analysis

“…Low birth weight is also considered a risk factor [ 36 ] and more specifically if it is below the third percentile [ 39 ], although other authors find no relationship [ 38 , 40 ].…”

“…The seasonal distribution of RSV reaches its maximum peak during the winter season, for some during the months of January–February [ 26 , 40 ], December–February [ 29 , 37 , 38 ], January–March [ 32 ], and February–May [ 42 ].…”

“…The environmental home conditions, such as the use of heating with stoves, are related to the number of cases of RSV infection, finding that these children present more serious episodes. In addition, exposure to tobacco is also considered a risk factor [ 26 , 29 , 40 ].…”

Maternal Risk Factors for Respiratory Syncytial Virus Lower Respiratory Tract Infection in Otherwise Healthy Preterm and Term Infants: A Systematic Review and Meta-analysis

“…18 Eight studies focused on preterm infants, 10,11,13–18 one was specific to term infants 12 and one covered both preterm and term infants. 9 A further 10 studies fulfilled the inclusion criteria, which included pooled or meta-analyses and risk factor modeling exercises. 3,4,19–26…”