Strategy
Chicago’s immunization program needed a way to assess RSV vaccination coverage among infants due to gaps that existed in the data for maternal and infant vaccine records. The program developed a strategy that connected vital records and immunization information system (IIS) data to create comprehensive data analysis.
Challenge
Chicago’s immunization program faced a challenge in accurately assessing RSV vaccination coverage among infants. The Illinois Comprehensive Automated Immunization Registry Exchange (I-CARE) did not link maternal vaccination records with infant records, creating gaps in understanding how well infants were protected at birth and in their early months with either maternal vaccination of Abrysvo or infant immunization with nirsevimab. Without this linkage, it was difficult to evaluate both maternal RSV vaccine uptake and infant nirsevimab administration. Birthing hospitals enrollment in the Vaccines for Children (VFC) program and challenges with I-CARE leaves inconsistencies in data reporting and coverage across the city’s birthing hospitals. These limitations made it difficult to assess timeliness of vaccine administration, identify disparities, and provide hospitals with feedback that could improve maternal and infant vaccination strategies.
Solution
To overcome these challenges, Chicago’s team developed a strategy to directly link maternal and infant records using birth certificates. By leveraging the city’s access to detailed Illinois vital records data and I-CARE, the program was able to match mothers and infants with viral records, identify which mothers received the RSV vaccine, and determine if their infants later received nirsevimab through I-CARE. This pairing allowed for a comprehensive analysis of coverage rates across the jurisdiction. Beyond vaccination status, the vital records data also contained valuable demographic and social information, such as insurance type, prenatal visits, and maternal country of origin. These details enabled the team to assess coverage disparities and highlight equity concerns, particularly differences between Medicaid and privately insured populations.
The team also stratified results by birthing hospital, which allowed them to evaluate institutional performance in ensuring timely protection of newborns. By conducting mid-season analyses and at the end of the RSV season, Chicago was able to provide actionable insights to hospitals and the broader immunization program.
Outcome
This innovative use of birth certificates to match maternal and infant records yielded a much clearer picture of RSV protection in Chicago. The approach revealed a larger picture in overall infant and maternal coverage and, notably, in the timeliness of vaccine administration within the first week of life. Stratifying data by birthing hospitals allowed program staff to identify tailored feedback and fostering accountability and improvement in immunization rates for the upcoming 2025-2026 RSV season. The analysis also uncovered disparities by insurance type and other demographic factors, equipping the program with evidence to target equity-focused messaging and interventions.
Additionally, the city saw progress in enrolling more birthing hospitals in the VFC program, broadening access to immunization. By embedding evaluation into annual cycles, the program positioned itself to adapt to new RSV products, such as clesrovimab versus nirsevimab administration, and to monitor trends in protection moving forward. Ultimately, the integration of vital records data into I-CARE data not only addressed technical data gaps but also strengthened Chicago’s ability to protect infants during their most vulnerable months.
Supplemental Materials