Delayed and incomplete immunization of children: cross-sectional community-based survey study among population of Kyiv, Rivne, and Volyn regions of Ukraine

Immunization is essential for preventing infectious diseases, yet timely vaccination remains a challenge globally, particularly in regions affected by war and disrupted healthcare infrastructure. Ukraine faces unique challenges, including systemic issues and vaccine hesitancy, impacting immunization timeliness. Aim - to determine the rate and characteristics of delayed immunization and its completeness among children in three regions of Ukraine. Material and methods. A cross-sectional, community-based survey was conducted at state and private primary healthcare facilities in Kyiv, Bucha, Rivne, and Lutsk. Data were collected via structured questionnaires, face-to-face parental interviews, and medical documentation review. Statistical analyses included descriptive statistics, chi-square tests, logistic regression, and Kaplan-Meier analysis. Results. Out of 152 children, 64.3% were fully vaccinated, but only 50% received timely vaccinations. The significant reasons for delays included untimely healthcare visits (29.2%), vaccine hesitancy (25.8%), and acute illness (18%). The presenсe of comorbidities in children was a statistically significant risk factor for delayed immunization. Kaplan-Meier analysis illustrated notable delays, especially for older children. Conclusion. This study identifies critical barriers to timely immunization, emphasizing the need for improved healthcare accessibility, targeted educational initiatives, and enhanced professional training. Further research is required to develop comprehensive interventions, particularly considering Ukraine's complex demographic challenges due to internal displacement of the population. The study was conducted in accordance with the principles of the Declaration of Helsinki. The study protocol was approved by the Local Ethics Committee for all participants. The informed consent was obtained from patients. The authors declare no conflict of interest.