Pediatr Pulmonol. 2025 Mar;60(3):e71022. doi: 10.1002/ppul.71022.
ABSTRACT
OBJECTIVE: To compare the Respiratory Syncytial Virus (RSV) hospitalization burden among 29-34 weeks gestational age (wGA) preterm infants between seasons with and without routine palivizumab prophylaxis, by utilizing the 2021 off-season RSV surge.
METHODS: This multi-center retrospective study was conducted in 11 medical centers across Israel. We included infants > 1 year-old, with wGA data, hospitalized with RSV infection from November 2017-August 2021. National palivizumab compliance data were collected separately. We compared two periods: in-season (November-March) with routine palivizumab prophylaxis as the reference, and off-season (April-October) without prophylaxis as the primary risk factor. The primary outcome was the proportion of RSV hospitalizations in 29-34 wGA infants relative to total RSV admissions, calculated separately for each period. Secondary outcomes included clinical severity parameters.
RESULTS: A total of 3296 infants were admitted during the RSV in-season, and 1044 during the off-season. National palivizumab compliance among eligible infants during the in-season study years was 91%-95%. The proportion of 29-34 wGA infants was significantly higher during the off-season compared to the in-season period (7% vs. 2.1%, p < 0.001). In a multivariable logistic regression model, the odds of hospitalization for 29-34 wGA preemies were 2.6 times higher during the off-season compared to the in-season (95% CI: 1.8-3.9, p < 0.001), independent of demographic covariates. Clinical severity was similar between the two periods.
CONCLUSIONS: Our results revealed a significantly higher proportion of 29-34 wGA infants hospitalized during seasons without palivizumab prophylaxis compared to seasons with palivizumab prophylaxis. These findings highlight the importance of including 29-34 wGA infants into future RSV immunoprophylaxis recommendations.
PMID:40042149 | DOI:10.1002/ppul.71022
