Parental Acceptance of Nirsevimab for RSV Prevention in Infants Across Two Consecutive Seasons in Emilia-Romagna, Italy.

Background: Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infection and hospitalization in infants. Nirsevimab, a long-acting monoclonal antibody, provides single-dose protection during the RSV season, but the effectiveness of prophylaxis programs depends on sustained parental acceptance and high uptake. This study evaluated changes in parental knowledge, perceptions, and willingness to accept nirsevimab across two consecutive RSV seasons in Emilia-Romagna, Italy. Methods: Two multicenter cross-sectional surveys were conducted during consecutive RSV seasons, 2024-2025 and 2025-2026, using a comparable questionnaire and recruitment approach. Parents or legal guardians of infants eligible for nirsevimab completed a semi-structured questionnaire during routine counseling in neonatal units. Survey 1 included 1042 respondents and survey 2 included 867 respondents. Sociodemographic characteristics, RSV awareness, knowledge and perception of nirsevimab, willingness to accept prophylaxis, trust in healthcare providers and the healthcare system, preferred information sources, and willingness to pay were compared between seasons. Results: Willingness to administer nirsevimab remained high and stable-87.04% in survey 1 and 88.00% in survey 2. Awareness of RSV-related risks increased from 68.23% to 73.47% (p < 0.05), and correct identification of nirsevimab as an antibody increased from 65.93% to 71.74% (p < 0.01). Explicit refusal rose slightly from 2.21% to 3.81% (p < 0.05). In survey 2, acceptance was associated with higher education, awareness of RSV risks, perceived child susceptibility, confidence in efficacy, lower concern about side effects, trust in pediatricians and the healthcare system, and willingness to pay. Notably, acceptance in 2025-2026 was higher among infants born in September-December than among those born in January-March, indicating a late-season decline. Conclusions: Parental acceptance of nirsevimab remained high across two seasons. Future campaigns should address residual knowledge gaps, reinforce communication on safety and efficacy, and sustain high coverage throughout the entire RSV season, particularly among infants born in its final months.