Impact of palivizumab immunization in controlling respiratory syncytial virus infections among preterm neonates after hospital discharge in the tropics

Background: Preterm neonates are at a greater risk of hospitalization for respiratory syncytial virus (RSV) infection and have significantly worse hospital outcomes compared with full-term neonates. Aim: To determine the incidence of RSV respiratory tract infections (RTIs) among preterm neonates aged < 29 weeks and/or 1000 g birth weight under a controlled palivizumab immunization program Materials and Methods: This was a prospective, observational cohort, single-center study. Preterm neonates, with or without palivizumab immunization, admitted to the NICU were monitored for 12 months after hospital discharge for RTI symptoms using a standard proforma through telephonic interview and further verification of hospital records. The presence of RSV was confirmed by real-time reverse transcription polymerase chain reaction on available nasal swab samples. Results: A total of 196 neonates were enrolled, of whom 55 (28%) neonates were palivizumab immunized (PVI) and 141 (72%) were nonpalivizumab immunized (NPV). The mean gestation of PVI neonates was 28.7 ± 2.2 weeks and their mean birth weight was 1.14 ± 0.41 kg; 43.6% of these PVI neonates had bronchopul-monary dysplasia. Overall, PVI neonates tested lower for RSV throughout the study period compared with NPV neonates. The number of neonates who required rehospitalization was more.