RSV-related hospitalization and outpatient palivizumab use in very preterm (born at <29 wGA) infants: 2003-2020

Birth characteristics as predictors of respiratory syncytial virus hospitalisation in newborns to optimise immunisation schedule

AIM

To examine birth characteristics that influence infant respiratory syncytial virus (RSV) hospitalisation risk in order to identify risk factors for severe RSV infections.

METHODS

Retrospective cohort study of 460 771 Sicilian children under 6 months old from January 2007 to December 2017. Hospital discharge records were consulted to identify cases and hospitalisations with International Classification of Diseases, Ninth Revision, Clinical Modification codes 466.11 (RSV bronchiolitis), 480.1 (RSV pneumonia) and 079.6 (RSV). RSV hospitalisation risk was estimated using adjusted odds ratios (aOR) and 95% confidence intervals (95% CI).

RESULTS

Overall, 2420 (5.25 per 1000 infants) RSV-related hospitalisations were identified during the study, with girls accounting for 52.8%. RSV hospitalisation risk increased for full-term, transferred, extreme immature, and preterm neonates with serious issues (aOR 3.25, 95% CI 2.90-3.64; aOR 1.86, 95% CI 1.47-2.32; aOR 1.54, 95% CI 1.11-2.07; and aOR 1.48, 95% CI 1.14-1.90). Compared to children born in June, the risk of RSV hospitalisation was significantly higher in children born in January (aOR 28.09, 95% CI 17.68-48.24) and December (aOR 27.36, 95% CI 17.21-46.99).

CONCLUSION

This study identified birth month and diagnosis-related groups as key predictors of RSV hospitalisations. This could help manage monoclonal antibody appropriateness criteria.

Liposomal Glutathione Augments Immune Defenses against Respiratory Syncytial Virus in Neonatal Mice Exposed in Utero to Ethanol

We previously reported that maternal alcohol use increased the risk of sepsis in premature and term newborns. In the neonatal mouse, fetal ethanol (ETOH) exposure depleted the antioxidant glutathione (GSH), which promoted alveolar macrophage (AM) immunosuppression and respiratory syncytial virus (RSV) infections. In this study, we explored if oral liposomal GSH (LGSH) would attenuate oxidant stress and RSV infections in the ETOH-exposed mouse pups. C57BL/6 female mice were pair-fed a liquid diet with 25% of calories from ethanol or maltose-dextrin. Postnatal day 10 pups were randomized to intranasal saline, LGSH, and RSV. After 48 h, we assessed oxidant stress, AM immunosuppression, pulmonary RSV burden, and acute lung injury. Fetal ETOH exposure increased oxidant stress threefold, lung RSV burden twofold and acute lung injury threefold. AMs were immunosuppressed with decreased RSV clearance. However, LGSH treatments of the ETOH group normalized oxidant stress, AM immune phenotype, the RSV burden, and acute lung injury. These studies suggest that the oxidant stress caused by fetal ETOH exposure impaired AM clearance of infectious agents, thereby increasing the viral infection and acute lung injury. LGSH treatments reversed the oxidative stress and restored AM immune functions, which decreased the RSV infection and subsequent acute lung injury.

Risk of RSV-related hospitalization is associated with gestational age in preterm (born at 29-34 wGA) infants without outpatient palivizumab administration

Palivizumab has been shown to decrease RSV-related hospitalization (RSVH) risk and reduce RSVH severity. American Academy of Pediatrics (AAP) guidance on administration of palivizumab has changed over time; in 2014, palivizumab was no longer recommended in preterm infants born at 29 weeks gestational age (wGA) or later. This study's objective was to describe RSVH risk and severity in preterm infants (29-34 wGA) without comorbidities relative to healthy term infants and to each other by gestational age. Using the MarketScan Multi-State Medicaid and Commercial Databases, infants born from July 1, 2014 to June 30, 2019, at 29-34 wGA (preterm) and >37 wGA (term) were identified. During RSV seasons (November to March) from 2014 to 2020, claims incurred by infants while they were <6 months old were evaluated for RSVH and RSVH characteristics. This study included 63,351 preterm infants and 1,076,389 term infants without outpatient palivizumab administration. Rate of RSVH was higher in infants with lower wGA at birth and ranged 3.32-5.72 per 100 infant-seasons in Medicaid-insured infants and 3.21-4.84 in commercially insured infants. Relative risk of RSVH was 5-8 times higher in Medicaid-insured preterm infants and 3-5 times higher in commercially insured preterm infants compared to term infants. ICU admissions and mechanical ventilation were more common during RSVH in preterm infants relative to term infants. RSV-related outpatient healthcare utilization was also 2-3 times higher in preterm infants born at 31-34 wGA. Increased utilization of palivizumab among infants born at 29-34 wGA may decrease RSVH rates and result in less severe course in preterm infants with RSVH.