Hospitalization for Respiratory Syncytial Virus Bronchiolitis in the Palivizumab Prophylaxis Era: Need for Reconsideration of Preventive Timing and Eligibility

Respiratory syncytial virus (RSV)-related bronchiolitis is a common cause of morbidity in young infants. The recommendations for its passive prevention by palivizumab are currently under intensive debate.To elucidate the optimal prevention strategy by studying the morbidity of RSV disease under the current recommendations for palivizumab prophylaxis in Israel.We collected demographic and clinical data of all children hospitalized with microbiologically confirmed RSV bronchiolitis during 2015-2016 at Schneider Children's Medical Center. The seasonality of RSV disease was also studied for the period 2010-2017 in sentinel clinics scattered throughout Israel.Of the 426 hospitalized children, 106 (25%) had underlying diseases but were not eligible for palivizumab prophylaxis according to the current criteria in Israel. Their course was severe, with a mean hospital stay of 6.7 days and a 12% admission rate to the pediatric intensive care unit (PICU). Palivizumab-eligible children who did not receive the prophylaxis before hospitalization had the most severe course, with 22% admitted to the PICU. More children were diagnosed with RSV disease in October than in March among both hospitalized and ambulatory children; 44% of the palivizumab-eligible hospitalized children were admitted in the last 2 weeks of October, before 1 November which is the recommended date for starting palivizumab administration in Israel.According to the results of the present study we suggest advancing RSV prophylaxis in Israel from 1 November to mid-October. The precise palivizumab-eligible categories should be reconsidered.