Social inequalities and vaccination coverage in the city of Salvador, Bahia

Abstract

Objective: To estimate the vaccination coverage in children born in the city of Salvador, analyzing these coverages by socioeconomic conditions. Method: A household survey on vaccination coverage was conducted with children born in 2005, in Salvador, Bahia, northeastern Brazil, who were aged between 18 to 36 months at the time of this study. Cluster sampling was performed in multiple stages. Census tracts were stratified using data from the national census conducted in 2000. Data was collected on socio-economic households. The sample size was defined by a specific methodology developed for immunization coverage surveys. The questionnaire was based upon the information contained in the vaccination cards. The estimated vaccination coverage in the various strata considered the sampling complex plan, weighting the observations according to the sampling fraction, the losses and the design effect. Results: There was inequality in the socioeconomic strata analyzed, where the coverage rate was directly proportional to socioeconomic status. Strata D and E showed statistically significant differences when compared to stratum A. Regarding to the complete scheme, children living in strata D and E have significantly less coverage than those residing in strata B. For vaccines not included in the basic scheme, the differences are very marked, showing less than 3% in stratum D and E. Conclusions: Vaccination coverage for the complete schedule at the end of 18 months of age with valid doses, was unsatisfactory and shows significant differences among the socio-economic strata with poor coverage in the poorest groups.