Respiratory Syncytial Virus Preterm (32-36 Completed Weeks Gestation) Risk Estimation Measure for RSV Hospitalization in Ireland: A Prospective Study

Abstract

BACKGROUND: In several countries RSV prophylaxis is offered to late preterm infants who are at escalated risk of respiratory syncytial virus hospitalization (RSVH). However, targeted prophylaxis should be informed by country specific data. This study, which uniquely includes 36 weeks gestational age (GA) infants, aims to establish the risk factors for RSVH in 32-36 weeks GA infants in Ireland. METHODS: A 13 hospital prospective observational study of laboratory confirmed RSVH in non-prophylaxed 32-36 weeks GA infants was conducted from July 2011- February 2014. Baseline and first year clinical data were analyzed using IBM SPSSV22. Significant (P<0.05) variables were entered into multiple logistic regression to determine independent risk factors for RSVH. RESULTS: Sixty-three percent of eligible infants (1,825/2,877) were recruited. The RSVH rate was 3.6 % (65/1807 analyzed infant records).There was no RSV attributable mortality. Twelve infants required intensive care. Of fifteen variables correlating to RSVH, five independent risk factors were identified: older siblings (OR 3.8; 95% CI 1.97, 7.41), being Caucasian (OR 2.3; 95% CI; 1.04, 5.29), neonatal respiratory morbidity (OR 2.2; 95% CI; 1.28, 3.94); birth 15 July-Dec15th (OR 2.1; 95% CI; 1.09, 3.92) and family history of asthma (OR 1.9; 95% CI; 1.01, 3.39). Birth 36 weeks to 36+6 days mitigated RSVH risk (RR 0.58; 95% CI; 0.34, 0.99), however risk factors were similar to the 32-35 weeks GA cohort. CONCLUSIONS: Neonatal respiratory morbidity or being Caucasian were population specific independent risk factors for RSVH in 32-36 weeks GA in Ireland whereas the other identified independent risk factors mirrored those established in previous studies.