Clinical Efficacy of Nirsevimab in Preventing Respiratory Syncytial Virus Infection in Preterm Infants

Objective :This study aims to evaluate the clinical efficacy of nirsevimab in preventing respiratory syncytial virus (RSV) infection in preterm infants. Methods :A total of 52 preterm infants admitted to the Department of Neonatology at Inner Mongolia Maternity and Child Health Gare Hospital between November 2024 and March 2025 were enrolled in this study. They were divided into a vaccinated group and a non-vaccinated group based on whether they received nirsevimab. Two groups received conventional treatment, while the vaccinated group additionally received nirsevimab to prevent RSV-associated respiratory infections. Clinical data, as well as diagnostic and therapeutic processes, were collected. The efficacy and safety of nirsevimab were evaluated, and the incidence and severity of RSV-associated respiratory infections in two groups were followed up. Results : (1) Compared with the non-vaccinated group, the efficacy rate of preventing RSV-associated respiratory infections was significantly higher in the nirsevimab vaccinated group (96.15% vs. 34.61%), with a statistically significant difference (P < 0.05). (2) In the non-vaccinated group, nine preterm infants (34%) developed RSV-associated respiratory infections, among whom 4 cases (15.3%) required non-invasive ventilator support, 2 cases (7%) experienced myocardial injury, 1 case (3.8%) had liver injury, and 1 case (3.8%) exhibited wheezing symptoms. (3) All preterm infants infected with RSV in the non-vaccinated group required rehospitalization, with an average hospital stay of 15.5 days; in contrast, no rehospitalization was required in the vaccinated group. (4) No significant adverse reactions were observed in the vaccinated group following nirsevimab injection. Conclusions :During the RSV epidemic season, prophylactic treatment with nirsevimab significantly reduces the incidence of RSV infection in preterm infants, decreases the risk of rehospitalization due to RSV infection, and demonstrates a favorable safety profile. Therefore, it is worthy of widespread application and promotion.