Delayed Vaccination and Related Predictors among Infants

Background: Vaccination status is more often evaluated by up-to-date vaccination coverage rather than timeliness of immunization. This study was conducted to evaluate delayed vaccination during infancy period and to determine the predictors effecting on vaccination delay. Methods: This cross-sectional study was conducted from June to September 2011 in Hamadan Province, the west of Iran, recruiting 2460 children from 12 to 24 months of age via stratified cluster random sampling with 123 clusters of 20 persons. Data on vaccination were extracted from children's vaccination card. Additional data were collected through interview. Results: Vaccination coverage of infants was >99.4% for all vaccines. However, 42% to 67.6% of infants received vaccine with delay. The delay time was longer in urban areas (P<0.001), among children with high educated mothers (P<0.001), and for the vaccines delivered at the end of infancy period. Delay time had a direct correlation with vaccinators' education level (P<0.001) and an inverse correlation with the number of periodical visits of health centers (P<0.001). No correlation was detected between delay time and gender (P=0.507) and distance from health centers (P=0.627). Conclusions: Considerable number of the infants received delayed vaccine, although, vaccination coverage was nearly completes. This issue indicates that delay time is very problematic to be resolved in any given situation even in areas with nearly full vaccination coverage and may require a major effort to be corrected. Furthermore, this study assessed the effect of some factors on delayed vaccination which may help policy makers who plan immunization programs.