Risk Factors for Hospitalization due to Lower Respiratory Tract Infection in Preterm Infants on Palivizumab Prophylaxis

To determine the risk factors associated with lower respiratory tract infections (LRTI) related hospitalizations in preterm infants receiving palivizumab throughout the high season for respiratory syncytial virus (RSV) infection. Premature infants who were commenced on palivizumab prophylaxis during the RSV season were included in the study following parental consent. Information on demographic, social, prenatal and postnatal clinical characteristics was recorded and risk factors associated with hospitalization were evaluated for each patient. While 234 participants (Group 1, 92.8%) did not require hospitalization during the study period, 18 patients (Group 2, 7.2%) were hospitalized at least once for LRTI during the RSV season. The rate of moderate-severe bronchopulmonary dysplasia (BPD) was significantly higher in group 2 compared to group 1 (38.9% vs 16.2%; P=0.016). Of the 18 infants who were hospitalized, 6 (33.3%) tested positive for RSV while the remaining 12 patients (66.7%) were negative for RSV. Odds ratio (OR) analysis of several risk factors revealed the presence of BPD (OR: 3.28; 95%CI: 0.19-9), a GA <28 weeks (OR: 1.6; 95%CI: 0.61-4.18), history of exposure to smoke (OR: 1.51; 95%CI: 0.52-4.38), being from a family with low socioeconomic status (OR: 3.64; 95%CI 1.08-12.3) to be associated with a higher likelihood of LRTI-related hospitalization. Our data demonstrated that RSV is an important LRTI agent and cause of hospitalization especially in preterm infants with additional risks such as BPD, gestational age of <28 weeks and low socioeconomic status. We suggest that improving care conditions and decreased BPD with prematurity would help in prevention of LRTI hospitalization.