Inequity in Timeliness of MMR Vaccination in Children Living in the Suburbs of Iranian Cities.

Introduction: High coverage of immunization is one of the indicators of good performance of health system but timely vaccination is another indicator which is associated with protective effect of vaccines. The present study aimed at evaluating the inequity in timely vaccination with a focus on inequities in timeliness by gender, birth order, parents' education and place of residence (rural or urban).

Methods: A historical cohort study was conducted on children of 24-47 months of age who were living in the suburbs of big cities in Iran and were selected through stratified proportional sampling method. Only children who had vaccine cards -i.e. 3610 children -were included in data analysis. The primary outcome was age-appropriate vaccination of MMR1. Inequity was measured by Concentration Index (C) and Relative Index of Inequity (RII). Inequity indexes were calculated according to the mother and father's education, child birth order, child's sex and the family's place of residence at the time of vaccination.

Results: The overall on-time MMR1 vaccination was 70% and 54.4% for Iranians and Non-Iranians, respectively. The C index of mother and father's education for timely MMR vaccination was 0.023 and was 0.029 in Iranian children as well as 0.044 and 0.019 for non-Iranians, respectively. The C index according to child order in Iranians and Non-Iranians was 0.025 and C=0.078. With regard to children who lived in cities, the on-time vaccination was 0.36% and 0.29% higher than that in rural areas . In male children it was 0.12% and 0.14% higher than that in female children for Iranians and Non-Iranians, respectively.

Conclusion: Timeliness MMR vaccination in Iranian children is higher than that in non-Iranian children. Regarding the existence of differences in timely vaccination rate in all Iranian and Non-Iranian children, no evidence was observed for inequity by focusing on parents' education, birth order, gender or place of residence. So, increasing timeliness of vaccination for enhancing the protective effect of vaccines can be considered a health-related goal in Iran after receiving high immunization coverage.