Respiratory syncytial virus hospitalizations in infants of 28 weeks gestational age and less in the palivizumab era

Objective: To obtain data on respiratory syncytial virus (RSV) associated hospitalization rates in preterm infants of 28 weeks gestational age and less in the era of palivizumab prophylaxis. Methods: Retrospective single-center cohort study including all preterm infants up to 28 weeks + 6 days gestational age and born between 2004 and 2012 at a tertiary care university hospital. Data on RSV related hospitalizations over the first two years of life covering at least two RSV seasons (November-April) were analyzed. Results: Ninety-one of 287 (32%) infants were hospitalized due to respiratory illness, and a total of 17 infants (5.9%) tested RSV positive during the first 2 years of life. Fourteen infants (4.9%) were hospitalized during the first RSV season. RSV hospitalization rate in infants with BPD was 4.5% (2/44) compared to 4.9% (12/243) without BPD. Palivizumab prophylaxis was documented in 74.6% of the infants. Infants with RSV compared to other respiratory tract infection were of younger age (6.8 vs. 9.1 months; p = 0.049), had longer hospital stays (median 11 vs. 5 days; p = 0.043) and more severe respiratory illness (median LRI score 3 vs. 2; p = 0.043). Conclusions: Despite palivizumab prophylaxis the burden of RSV disease and all cause respiratory illness was still remarkable in this vulnerable preterm population and mainly limited to the first season