Epidemiology of Respiratory Syncytial Virus-related Hospitalizations and the Influence of Viral Coinfections in Southern Austria in a 7-year Period.

OBJECTIVE: The aim of this study was to determine the respiratory syncytial virus (RSV) epidemiology and to analyze the influence of risk factors and coinfections over the last years. METHODS: Retrospectively all infants, children and adolescents hospitalized due to respiratory disease with positive RSV test [hospitalized for RSV infection (RSV-H)] between January 1, 2009, and December 31, 2015, at a tertiary care center in the southern part of Austria were included for analysis. Patients were all identified by a search via International Classification of Diseases and Related Health Problems, 10th Edition codes, and all medical data were collected from the local electronic databases called openMedocs. RSV tests had to prove true infection case definition. RESULTS: During a 7-year study period, 745 infants, children and adolescents exhibited RSV-H. Main diagnosis was bronchiolitis (70%). Nearly half of all cases (44%) were born during the first half of the RSV season (November-January), and seasonal peak of RSV-H was in January. Predominant underlying condition was history of prematurity in 15% followed by neurologic impairment (3.5%) and hemodynamically significant congenital heart disease (2.95%). Age ≤2 months and underlying conditions/morbidities were associated with more severe disease. The majority of cases (96%) had an age below 24 months, and 91% below 12 months. Viral coinfection (most common influenza virus, adenovirus and rhinovirus) was diagnosed in 37 cases (5%) resulting in a more severe course of disease. Main risk factors of coinfection were siblings and crowding. Mortality was 0.27% (2/745). Both children had coinfection with influenza A virus and were multihandicapped (15 and 20 years of age, respectively). CONCLUSIONS: Prematurity and underlying morbidities play a marked role in RSV-H. Viral coinfections aggravated disease with death in 2 multihandicapped adolescents.

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

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.