O3232: Knowledge and acceptance of Nirsevimab and RSV vaccine among mothers of in-hospital newborns,Lima,Peru,2025.

Background: Respiratory syncytial virus (RSV) is the most predominant etiologic agent in lower respiratory infections in newborns and infants, associated with 3-9% mortality in children under 5 years and mainly affects low- and middle-income countries. Preventive methods have been developed and are available in most high-income countries. The study aimed to have a first pre-immunization insight into parental knowledge and acceptance about Nirsevimab and RSV vaccines, which are expected to become available soon in Peru. Maternal knowledge and attitudes towards vaccines are strong determinants for acceptance, which could enhance RSV immunization coverage and reduce the burden of RSV-related hospitalizations in infants.

Methods: This was a cross-sectional, prospective, and analytical study approved by the Peru Ethics Committee. Written informed consent was obtained in person from the mothers. A structured questionnaire was distributed to mothers of neonates delivered at the Edgardo Rebagliati Martins Hospital during March–April 2025. We evaluated knowledge and acceptance of preventive products against RSV (RSVPP). Questionnaire data were collected following content validation by expert judgment and a pilot study (n=30), before starting enrollment. To explore factors associated with the acceptance of RSVPP, crude and adjusted prevalence ratios (PRs) with 95% CIs will be estimated using GLMs (Poisson family).

Results: The estimated sample size for this study is approximately 350 participants. Our preliminary data includes 100 mothers enrolled with a mean age of 34.0 ± 5.9 years and 70% with higher education. Median household income was $810.8 (IQR: $540.5–$1,081.1). Parental comorbidities were low (8.2%). Majority of newborns were female (55%), born at term (79%), from general ward rooms (84%), and only 10% had major comorbidities. Median time of questionnaire administration was two days after birth (IQR: 1–3 days). Most participants never heard of RSV infection (96%) or the RSV maternal vaccine (97%), and none were aware of Nirsevimab. Overall tendency to accept RSVPP was favorable (Figure1), with acceptance rates of 63% for the maternal vaccine, 65% for Nirsevimab, and 61% for a future infant vaccine. With respect to factors associated with acceptance of these products, parents who worked in healthcare (adjusted PR: 1.46; 95% CI: 1.08–1.98; p=0.015) and those with a family history of prematurity (adjusted PR: 1.45; 95% CI: 1.08–1.95; p=0.012) were significantly associated with acceptance of Nirsevimab, after adjusting for sex and newborn prematurity. No other factors were found to be associated with acceptance of the maternal vaccine or the future infant vaccine (Table1).

Conclusion: Most mothers never heard of RSVPP; however, acceptance was around 60%. Mothers who worked in the healthcare sector or had a family history of prematurity were more likely to accept Nirsevimab. Further efforts are needed to promote awareness and education about these products, especially in LMIC settings.