timing and delay in children vaccination; evaluation of expanded program of immunization in outskirt of iranian cities

background: most studies evaluated the vaccine coverage, but the time of vaccination is important as coverage. this study was conducted to evaluate the expanded program of immunization (epi) in outskirt of iranian cities regarding to incidence of delay vaccination among children less than 4 years. methods : this cross sectional descriptive study was conducted among children 24-47 months old, living in the suburbs of five metropolises of iran. totally, 3610 eligible children selected with proportione d cluster sampling method and data of vaccination card extracted after interview with child parents. delayed incidence rate reported and predictive factors assessed by chi square test and multivariate logistic regression. results: overall, 56.6% to 93.2% vaccines were administered out of time. delayed vaccination incidence with more than one-week delay varies from 5.5 % to 74.9 % for polio at birth and mmr2 at 18 month, respectively. mother’s educational level and birth order were the most important predictors of delayed vaccination . incidence of delayed vaccination was enlarged by increasing birth order and decreased in lower educated mothers. conclusions: incidence rate of delayed vaccination is more than expectation. regarding to high coverage vaccines in iran, heath officers and health policy makers should attempt for on-time vaccination beside of high immunization coverage especially in slum areas with more concentrated immigrants due to low literature and crowded families.