Challenges in the prophylaxis of severe respiratory syncytial virus infections

To analyze palivizumab prophylaxis adherence among newborns and infants, as well as identify its challenges and facilitators.

This retrospective study reviewed medical records of individuals who received palivizumab between 2008 and 2019 at a referral center in a metropolitan city in Brazil. Three adherence criteria were evaluated: an adequate number of doses received, interval between doses ≤ 35 days, and complete adherence (meeting both prior criteria). Associations between these criteria and sociodemographic/clinical variables, as well as post-prophylaxis bronchiolitis-related hospitalizations, were examined.

A total of 908 participants (mean age 6.7 months,50.8 % male,57.8 % residing in the city) were analyzed. During the three-season study period, a total of 1,158 doses were prescribed, and complete adherence was observed in 44.5 % of cases. Based on both the adequate number of doses and complete adherence criteria, lower adherence was noted among those living outside the city (52.8 % vs.60.9 %, p = 0.01; and 41.5 %vs.48.5 %, p = 0.03, respectively) and infants born to mothers younger than 20 years (39.7 % vs.60.3 %,p < 0.01; and 31.5 %vs.68.5 %, p = 0.02, respectively). Infants with gestational age < 28 weeks (65.8 % vs.34.2 %, p = 0.03) and birth weight < 1000 g (67.8 % vs.32.2 %, p = 0.03) had higher adherence under the adequate number of doses criterion. No association emerged between adherence and bronchiolitis-related hospitalizations, which were predominantly linked to maternal smoking during pregnancy and chronic lung disease.

Adherence to palivizumab prophylaxis was low, highlighting the need to address geographic barriers and maternal age factors. Extreme prematurity and very low birth weight facilitated adherence, indicating that more targeted strategies or decentralized administration may improve outcomes in high-risk populations.