Completeness and timeliness of vaccination and determinants for low and late uptake among young children in eastern China

Background: We studied completeness and timeliness of vaccination and determinants for low and delayed uptake in children born between 2008 and 2009 in Zhejiang province in eastern China. Methods: We used data from a cross-sectional cluster survey conducted in 2011, which included 1146 children born from 1 Jan 2008 to 31 Dec 2009. Various vaccination history, social-demographic factors, attitude and satisfaction toward immunization from caregivers were collected by a standard questionnaire. We restricted to the third dose of HepB, PV, and DPT (HepB(3), PV3, and DPT3) as outcome variables for completeness of vaccination and restricted to the first dose of HepB, PV, DPT, and MCV(HepB(1), PV1, DPT1, and MCV1) as outcome variables for timeliness of vaccination. The chi(2) test and logistic regression analysis were applied to identify the determinants of completeness and timeliness of vaccination. Survival analysis by the Kaplan-Meier method was performed to present the timeliness vaccination. Results: Coverage for HepB(1), HepB(3), PV1, PV3, DPT1, DPT3, and MCV1 was 93.22%, 90.15%, 96.42%, 91.63%, 95.80%, 90.16%, and 92.70%, respectively. Timely vaccination occurred in 501/1146(43.72%) children for HepB(1), 520/1146(45.38%) for PV1, 511/1146(44.59%) for DPT1, and 679/1146(59.25%) for MCV1. Completeness of specific vaccines was associated with mother' age, immigration status, birth place of child, maternal education level, maternal occupation status, socioeconomic development level of surveyed areas, satisfaction toward immunization service and distance of the house to immunization clinic. Timeliness of vaccination for specific vaccines was associated with mother' age, maternal education level, immigration status, siblings, birth place, and distance of the house to immunization clinic. Conclusion: Despite reasonably high vaccination coverage, we observed substantial vaccination delays. We found specific factors associated with low and/or delayed vaccine uptake. These findings can help to improve strategies such as Reaching Every District (RED), out-reach vaccination services and health education to reach children who remain inadequately protected.