Differences in routine childhood immunization uptake between single and multiple healthcare facility use: the Kochi Adjunct Study of Japan Environment and Children's Study.

BACKGROUND

The efficacy of routine childhood immunization depends on timely vaccine uptake and facility use patterns. This study examined the association between pediatric vaccination facility use patterns and routine childhood immunization uptake among children up to age eight years.

METHODS

As part of the Kochi Adjunct Study of the Japan Environment and Children's Study (JECS), we analyzed data from 1,644 participants whose Maternal and Child Health Handbook photographs were collected in the eighth year of the cohort study. Maternal and Child Health Handbook records determined immunization completion. Participants were categorized into four groups based on pediatric vaccination facility use patterns: single facility use throughout, multiple facility use during the first period, multiple facility use during the second period, and multiple facility use throughout both periods. Maternal and child characteristics were collected via paper-based questionnaires. Associations between facility use patterns, sociodemographic factors, and immunization completion were analyzed using chi-square tests and logistic regression.

RESULTS

Overall, routine childhood immunization completion was observed in 1,259 (76.6%) participants. Chi-square tests indicated that marital status, educational level, lower parity, never smoking, not attending nursery, and breastfeeding practice for infants aged four months old were significantly associated with routine childhood immunization completion. Single facility use throughout the immunization period was observed in 1,011 (61.5%) participants. Multiple facility use (38.5%) was associated with higher odds of routine childhood immunization incompletion than single facility use. This association was the strongest for those who used multiple facilities throughout the vaccination period (adjusted odds ratio, 1.90; 95% confidence interval, 1.24-2.91).

CONCLUSIONS

Single pediatric facility use was associated with higher routine immunization uptake. Our findings suggest that encouraging the use of one medical institution for a child's vaccinations may be a useful approach to consider when addressing vaccination coverage challenges.