Abstract: Objective　To analyze the effectiveness and safety of nirsevimab injection in preterm infants at high risk of severe respiratory syncytial virus（RSV） infection. Methods　This was a retrospective study. The clinical data of 75 preterm infants at high risk of severe RSV infection were collected，who received nirsevimab when discharged from Gansu Provincial Maternal and Child Healthcare Hospital（Gansu Provincial Central Hospital） from September 2024 to March 2025，with follow-up for acute respiratory infections（ARIs） and adverse reactions within 5 months after discharge. Results　In the 75 child patients，41 were male and 34 were female. The median age at injection was 56（34，74） d， adjusted chronological age was 37（35+4，38） w， and median weight was 2180（1930，2440） g. Among these infants，74（98.7%） were low birth weight infants，67（89.3%） were preterm infants with a gestational age of ≤32 weeks， and 37（49.3%） had extrauterine growth restriction（EUGR）. Most parents had some knowledge of RSV disease and the efficacy and safety of nirsevimab. During the follow-up，only 1 case（1.3%） developed RSV infection；this infant had a history of severe bronchopulmonary dysplasia（BPD） and was complicated with temporary hypogammaglobulinemia，and was cured and discharged after 9 days of mechanical ventilation. Adverse reactions occurred in 2 cases（fever in 1 case，local pain in 1 case），both of which resolved spontaneously within 48 hours.　Conclusion　Nirsevimab injection in preterm infants at high risk of severe RSV infection can effectively reduce the incidence of RSV infection with good safety profile.

Key words: preterm infants, respiratory syncytial virus, nirsevimab, adverse reactions

摘要： 目的　分析存在严重呼吸道合胞病毒（respiratory syncytial virus，RSV）感染高风险的早产儿注射尼塞韦单抗的有效性及安全性。方法　采用回顾性研究方法，收集2024年9月至2025年3月在甘肃省妇幼保健院（甘肃省中心医院）出院时注射尼塞韦单抗的、存在严重 RSV 感染高风险的早产儿75例临床资料，随访出院后5个月内发生急性呼吸道感染（acute respiratory infections， ARIs）及不良反应情况。结果　75例患儿中男41例、女34例。注射尼塞韦单抗中位日龄为56（34，74）d，矫正中位胎龄37（35+4，38）周，中位体重2180（1930，2440）g。其中低出生体重儿74例（98.7%），≤32周早产儿67例（89.3%），伴宫外生长发育迟缓（extrauterine growth restriction，EUGR） 37例（49.3%）。大部分家长对 RSV 疾病及尼塞韦单抗的有效性及安全性有一定认知。随访期间，仅1例（1.3%）发生 RSV 感染，该例既往伴重度支气管肺发育不良（bronchopulmonary dysplasia，BPD），此次合并婴儿暂时性低丙种球蛋白血症，有创呼吸机治疗9 d 后治愈出院。发生不良反应2例（发热1例，局部疼痛1例），均于48 h 内自行缓解。结论　对存在严重 RSV 感染高风险的早产儿注射尼塞韦单抗，可有效降低 RSV 感染发生率，安全性良好。

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