Background: The newly approved respiratory syncytial virus (RSV) monoclonal antibody (MA), released autumn of 2023, is an important prevention measure against severe infection in newborns. This analysis examines data from the local immunization information system (IIS) to identify factors associated with receipt of MA.

Objective(s): Examine the relationship between demographic, regional, and other health indicators, and the probability of having received MA. Healthy Places Index (HPI) quartiles, assess neighborhood health equity calculated using twenty-three social determinants of health factors.

Methods: Data for this analysis were obtained from the IIS and study population included County of San Diego resident babies who were born between January 1, 2023 - February 29, 2024. Babies who received MA were compared to those who did not but received at least one other vaccine in same timeframe. Associations were estimated using multivariate logistic regression.

Results: This model showed several factors were significantly associated with having received MA. Several racial minority groups were more likely to have received MA (Asian, Black, and Other; OR=1.3, 1.2, and 1.9, p < 0.01) as compared to the referent group of Whites. There was a negative relationship between HPI and receipt of MA (highest HPI compared to lowest HPI; OR = 0.74, p < 0.001).

Conclusion: HPI and other demographics reliably predict the probability of having received MA during its first season of availability and could be utilized by public health professionals to focus limited resources. Further understanding of vaccine-related narratives is needed to effectively address the gap in vaccine inequalities.