Immunization Gaps Among Perinatally HIV-Exposed, Uninfected Children: A Single-Centre Study of Documented Vaccination Records

Background/Objectives: Children exposed to HIV perinatally but remaining uninfected (HEU) may represent a vulnerable population for preventive healthcare. This study assessed age-appropriate vaccination completeness among HEU children in Romania and explored its distribution across birth cohorts and selected sociodemographic characteristics. Methods: We conducted a retrospective observational cohort study including children born to women living with HIV and enrolled in a prevention of mother-to-child HIV transmission program between 2005 and 2024. Vaccination data were obtained from the Romanian National Electronic Vaccination Registry. Vaccination completeness was assessed according to the national immunization schedule applicable to each child’s year of birth, using an age-eligible vaccine completeness score. Results: Among 139 HEU children evaluated, the mean vaccination completeness score was 60.4% (SD 29.0%), with a median of 69.4% (IQR 44.3–80.6%). Overall, 70.5% of children had scores below 80%, whereas only 13.0% achieved ≥90% completeness. BCG had the lowest documented coverage (14.4%), while MMR showed the highest vaccine-series completion, although still suboptimal. Important gaps were observed for several vaccines, particularly among older cohorts. Vaccination patterns differed significantly across birth cohorts, while the analyzed sociodemographic characteristics did not consistently explain these differences. Conclusions: Vaccination completeness among HEU children in this Romanian cohort was substantially below recommended targets, despite their follow-up within a specialized healthcare setting. The findings suggest persistent gaps in preventive care and highlight the need for systematic vaccination monitoring, timely catch-up strategies, and improved continuity of care throughout the transition from HIV-exposure follow-up to routine pediatric services.