Up-to-date or Complete Immunization Coverage and Their Related Factors

Lee, Moo Sik; Kim, Eun Young; Kim, Keon Yeop; Lee, Jin Yong; Jang, Min Young; Hong, Jee Young

Abstract

OBJECTIVES
Understanding the predictor of immunization status in childhood is critical issue to improve National Immunization Program (NIP). The aims of this study were to verify the status of up-to-date or complete immunization coverage and to investigate its related factors.
METHODS
As of 2005, according to local residence registry data, there were 2,188 children who aged 12 to 35 months in Nonsan city, Korea. We conducted household survey for aged 12 to 35 months children, using questionnaires to obtain data on the status of immunization such as BCG, DTaP (diphtheria, tetanus, and pertussis), Polio, and MMR (mump, measles, rubella). Finally 1,472 participated in the survey. The operating definitions used in this study were following; "Complete immunization rate" refers to the rate of children who received all immunization within recommended age intervals fully "on-time"; "The 4:3:1 series" means status of receiving the fourth diphtheria-tetanus-pertussis (4 DTP), the third Polio (3 Polio), and the first measles-mumps-rubella (1 MMR) doses. Multivariate logistic regression analyses were used to determine factors affecting complete vaccination coverage of children.
RESULTS
Immunization rates of vaccine based on the vaccination card were from 92.7% to 96.4% except 4th DTaP (79.3%). Complete immunization rate of Korea NIP was 74.0% and that of the 4:3:1 series was 77.1%. A parent as primary caregiver (OR 0.59, 95% CI 0.39-0.87 at 19-35 months of children's age) and first-born children (OR 1.79, 95% CI 1.05-3.03 at 24-35 months of children's age) were significantly related to complete immunization coverage of Korea NIP. And a parent as primary care giver (OR 0.58, 95% CI 0.38-0.88 at 19-35 months of children's age) and first-born children (OR 1.94, 95% CI 1.21-3.14 at 19-35 months, OR 2.23, 95% CI 1.27-3.91 at 24-35 months of children's age) were significantly related to complete immunization rate of 4:3:1 series.
CONCLUSIONS
Government should take actions to increase complete immunization rate. In particular, intervention on the secondary caregiver and non-first-born children should be needed.