Timeliness gap in non‑EPI Childhood vaccination in urban China: a five-city study of socioeconomic determinants and caregiver preferences.
BACKGROUND Delays in receiving vaccinations lead to higher vaccine-preventable disease risk. We quantified the prevalence and drivers of delayed uptake of fee‑based, non-Expanded Program on Immunization (non-EPI) childhood vaccines in urban China. METHODS A multicentre clinic-based survey with an embedded discrete-choice experiment (DCE) was conducted from May to July 2024 in 15 immunisation clinics across five provincial capitals in China. Caregivers of children aged 0-6 years provided verified vaccination information, socio demographic data, scores on a 12 item Caregiver Timely Vaccination Scale, and responses to a DCEwith four attributes (price, waiting time, calendar delay, adverse event [AE] risk). Delayed vaccination was defined as receipt of at least one non-EPI dose 30 days or more after the recommended schedule.Weighted logistic regression identified correlates; mixed logit models generated marginal utilities and willingness to pay (WTP). RESULTS Among 1 292 valid caregiver-child pairs, the delay prevalence was 23.7% (95%CI: 21.3-26.1). Delay risk increased with monthly household income < ¥10 000 (adjusted OR: 1.24, 95% CI: 1.11-1.38), an unpleasant prior vaccination experience (1.11, 1.01-1.23) and a caregiver's delay history (1.22, 1.10-1.36), and less likely when knowledge was adequate (0.33, 0.25-0.43). The timely scale discriminated delayed from timely caregivers (+ 1.0 mean score). In the DCE, AE risk dominated all other attributes (66.3% relative importance): lowering the stated risk from 5% to 3% increased predicted uptake by 74% points. Reducing queue time from 30 min to 10 min added 24 points. Caregivers were willing to pay ¥106 (≈ US $14) per 1% AE‑risk reduction but only ¥4 for a 10‑day improvement in calendar timeliness. CONCLUSIONS Delayed vaccination drives non-EPI under timeliness in urban China. Embedding delay metrics and the brief 3 C screen in routine dashboards, supported by sharper AE‑risk communication and fast‑track queues, could close the gap and advance Immunization Agenda 2030 targets.