Evaluation of a campaign to improve immunization in a rural headstart program

Abstract

This study evaluated an intervention to improve immunization rates in a high poverty, medically underserved rural area employing a pretest-posttest design. The intervention expanded immunization availability, established walk-in appointment policies, and introduced intensified parent education. Formative evaluation indicated specific messages with high salience to parents. As a result, the susceptibility and severity of childhood infectious disease, the outcome efficacy of vaccines, and methods to reduce barriers to immunization were emphasized in communications with parents. Data on DTP1-4, OPV1-3, and MMR were obtained from preschools, local health departments and private medical practices before (n = 567) and after the intervention (n = 331). Following adjustment for birth order and demographics, at post-intervention a significantly greater proportion of children received 6 of 8 vaccines on time. Effect sizes were large. For example, post MMR rates were at least 2X greater than pre rates. Time-series analysis of trend data on local newspaper coverage of child health topics suggested history was not a major threat to the internal validity of this pre-post only design. The findings indicate that comprehensive intervention, targeting improvements in the availability of pediatric care, health system policies and parent behavior, can improve immunization.