Abstract

This study evaluated the impact of transferring the thirteen‑year tetanus-diphtheria booster from schools to Family Health Centers on vaccination coverage after 1 July 2020. In a two‑component descriptive cross‑sectional design conducted in the central districts of Şanlıurfa Province, annual non‑vaccination from 2018 to 2022 was tracked using administrative records; in addition, reasons for non‑vaccination were classified through face‑to‑face interviews with family physicians and on‑screen verification in nineteen Family Medicine Units selected by two‑stage stratified sampling. The primary outcome was non‑vaccination for the tetanus-diphtheria dose at age thirteen. In the research group, non‑vaccination was 23.5% in 2018, 27.2% in 2019, 22.2% in 2020 (annual total), 13.2% in 2021 and 12.3% in 2022; within 2020, rates were 32.4% before July and 11.9% after July. The absolute pre‑ versus post‑policy difference was 14.4% points and the relative risk was 0.47; the three districts likewise showed consistent declines in 2021-2022 compared with 2018-2019. Leading reasons for non‑vaccination were failure to attend after expressing intent (49.1%), outright refusal (20.9%), migration‑related mobility (13.5%), and doses administered elsewhere that were not visible in the records (8.6%). Relocating delivery to Family Health Centers strengthened access and follow‑up and was associated with improved coverage; yet intention-behaviour gaps, mobility and data fragmentation still limit attainment of the national threshold. A hybrid model combining school‑based visits with targeted completion at Family Health Centers may provide a pragmatic, low‑cost route to reach remaining groups.