Vaccination coverage and its determinants among migrant children in Guangdong, China.

Background: Guangdong province attracted more than 31 million migrants in 2010. But few studies were performed to estimate the complete and age-appropriate immunization coverage and determine risk factors of migrant children.

Methods: 1610 migrant children aged 12-59 months from 70 villages were interviewed in Guangdong. Demographic characteristics, primary caregiver's knowledge and attitude toward immunization, and child's immunization history were obtained. UTD and age-appropriate immunization rates for the following five vaccines and the overall series (1:3:3:3:1 immunization series) were assessed: one dose of BCG, three doses of DTP, OPV and HepB, one dose of MCV. Risk factors for not being UTD for the 1:3:3:3:1 immunization series were explored.

Results: For each antigen, the UTD immunization rate was above 71%, but the age-appropriate immunization rates for BCG, HepB, OPV, DPT and MCV were only 47.8%, 45.1%, 47.1%, 46.8% and 37.2%, respectively. The 1st dose was most likely to be delayed within them. For the 1:3:3:3:1 immunization series, the UTD immunization rate and age-appropriate immunization rate were 64.9% and 12.4% respectively. Several factors as below were significantly associated with UTD immunization. The primary caregiver's determinants were their occupation, knowledge and attitude toward immunization. The child's determinants were sex, Hukou, birth place, residential buildings and family income.

Conclusions: Alarmingly low immunization coverage of migrant children should be closely monitored by NIISS. Primary caregiver and child's determinants should be considered when taking measures. Strategies to strengthen active out-reach activities and health education for primary caregivers needed to be developed to improve their immunization coverage.