Predictors and incidence of hospitalization due to respiratory syncytial virus (RSV)-associated lower respiratory tract infection (LRTI) in non-prophylaxed moderate-to-late preterm infants in Bosnia and Herzegovina.

Prematurity is a risk factor for respiratory syncytial virus (RSV)-associated lower respiratory tract infections (LRTIs), due to immature humoral and cell-mediated immune system in preterm newborns, as well as their incomplete lung development. Palivizumab, a humanized monoclonal antibody against the F glycoprotein of RSV, is licensed for the prevention of severe RSV LRTI in children at high risk for the disease. This study is a part of a larger observational, retrospective-prospective epidemiological study (PONI) conducted at 72 sites across 23 countries in the northern temperate zone. The aim of our non-interventional study was to identify common predictors and factors associated with RSV LRTI hospitalization in non-prophylaxed, moderate-to-late preterm infants, born between 33 weeks and 0 days and 35 weeks and 6 days of gestation, and less than 6 months prior to or during the RSV season in Bosnia and Herzegovina (B&H). A total of 160 moderate-to-late preterm infants were included from four sites in B&H (Sarajevo, Tuzla, Mostar, and Banja Luka). We identified several significant intrinsic and extrinsic factors to be associated with the risk of RSV LRTI hospitalization in the preterm infants, including: comorbidities after birth, shorter hospital stay, admission to NICU/PICU while in the maternity ward, household smoking, low maternal age, breast feeding, number of family members, and history of family/paternal atopy. Overall, our results indicated that the risk of RSV LRTI in preterm newborns can be associated with different environmental and social/cultural factors, and further research is needed to comprehensively evaluate these associations.