230 - Assessing uptake of RSV immunization for infants during its inaugural rollout

Publication Number: 230.3878

Alistair S. Mukondiwa, Wake Forest Baptist Health - Brenner Children's Hospital, Winston-Salem, NC, United States; Brian N. White, Wake Forest School of Medicine of Wake Forest Baptist Medical Center, Winston-Salem, NC, United States; Cara B.. Janusz, Wake Forest School of Medicine of Wake Forest Baptist Medical Center, Winston Salem, NC, United States; Laurie W. Albertini, Wake Forest School of Medicine of Wake Forest Baptist Medical Center, Winston Salem, NC, United States; Stephen M. Downs, Wake Forest School of Medicine of Wake Forest Baptist Medical Center, Winston Salem, NC, United States; Callie L. Brown, Wake Forest School of Medicine of Wake Forest Baptist Medical Center, Winston-Salem, NC, United States

Background: Respiratory Syncytial Virus (RSV) is a leading cause of hospitalization among young children. The recent approval of the world’s first RSV vaccine for use in pregnant persons and preventive, long-acting monoclonal antibody (mA) for use in infants with and without underlying health conditions was a groundbreaking milestone, but the rollout was accompanied by supply chain and distribution challenges and public distrust.

Objective: We aimed to assess the rate of RSV immunization of infants born at a large academic birth center, Atrium Health Wake Forest Baptist (AHWFB), located in North Carolina and followed at affiliated outpatient pediatric clinics (and therefore had data on both maternal vaccination and infant receipt of mA). We also aimed to examine differences in immunization status by demographic factors and clinic site.

Design/Methods: Retrospective data was extracted from the electronic health record for infants with deliveries at AHWFB between 01/01/2023-04/30/2024 and seen at one of 12 AHWFB outpatient pediatric clinics between 08/01/2023-04/30/2024.We examined descriptive statistics using percentages and median (IQR) for categorical and continuous variables, respectively, and used chi-square tests to assess the associations between immunization and demographic factors, including gestational age, race, ethnicity, insurance status, maternal age, and the clinic at which the infant received care.

Results: During the eligible time there were 1,110 infants who met inclusion criteria. Uptake of RSV immunization via maternal vaccination or infant mA antibody receipt was 12.5%. In bivariate analyses, infants had higher immunization rates if they had an older gestational age, public insurance, Hispanic ethnicity, or spoke Spanish (Table 1). Immunization rates varied by clinic site, with 3 clinics administering no mA and other rates varying from 3.2-18%. The resident continuity clinic, serving majority Medicaid and Hispanic patients, had the highest mA administration rate at 18%. In multivariable analyses, infants with public insurance or uninsured had significantly higher odds of immunization than infants with private insurance (Table 2).

Conclusion(s): Our findings suggest overall low uptake of RSV immunization in its first year and differences in immunization rates by insurance status, which is likely at least partly due to variations in clinics' procurement challenges, administration practices, and priorities. Future qualitative research should explore parents' reasons for low maternal and infant immunization against RSV, and clinics' reasons for offering or prioritizing the mA's administration.

Table 1
Participant Demographics by Infant Immunization Status

Table 2
Multivariable analyses examining the odds of infant immunization (via maternal vaccination or infant receipt of monoclonal antibody)