Impact of the COVID-19 pandemic on the spatiotemporal distribution of special immunobiological requests for preterm newborns

Immunization of preterm newborns (PTNB), although widely recommended, remains a challenge due to prolonged hospitalization, hesitation among healthcare professionals, and the absence of standardized guidelines. The COVID-19 pandemic intensified this scenario by disrupting vaccination services, leading to reductions in vaccine coverage. To analyze the impact of the COVID-19 pandemic on the spatiotemporal distribution of special immunobiological requests for PTNB in the state of Minas Gerais, Brazil, between 2019 and 2024. A mixed ecological time-series study was conducted across 853 municipalities in 16 health macro-regions of Minas Gerais. Requests for special immunobiologicals registered between 2019 and 2024 were analyzed using data from the Information System of the Reference Centers for Special Immunobiologicals (SI-CRIE). Analyses combined descriptive statistics, Getis–Ord Gi* for spatial clustering, and structural-break tests (Chow, Bai–Perron, Zivot–Andrews) with segmented regression. Requests rose in 2020 (22.3% vs. 3.8% in 2019), declined during the pandemic (13.1% in 2021; 7.1% in 2022), and recovered thereafter (16.8% in 2023; 36.9% in 2024), with significant breaks around 2020–2022. Spatial distribution was heterogeneous across macro-regions. Coldspots predominated in the North, Jequitinhonha, and East, reaching 61.7% of municipalities in 2022. In the post-pandemic years, hotspots emerged in Central and Southern regions, with the largest hot cluster observed in 2024. The decline in special immunobiological requests for PTNB during the pandemic reflected the impacts of the health crisis. Spatial heterogeneity underscores the need for regional strategies to expand equity in vaccine access.