Tracking immunization coverage, dropout and equity gaps among children ages 12–23 months in Malawi – bottleneck analysis of the Malawi Demographic and Health Survey

BACKGROUND: Between 2010 and 2016, the proportion of children 12–23 months of age who received full immunization in Malawi decreased from 81% to 76%. Most studies on immunization have mainly focused on the risk factors of vaccination coverage while data on dropouts and equity gaps is very scanty. Thus the aim of the present study was to describe the trend in immunization coverage, dropout rates and effective immunization coverage (EIC) among children ages 12–23 months in Malawi. METHODS: Secondary analyses of the cross-sectional data obtained from the three waves of the Demographic and Health Surveys (2004, 2010 and 2015–16) were conducted. Using bottleneck analysis, outputs were generated based on service coverage, demand/equity (service utilization) and quality (full immunization). The World Health Organization benchmarks were used to assess gaps in the immunization coverage indicators. RESULTS: The coverage was >90.0% in most of the antigens while full immunization status was estimated at 65%, 84% and 73% in 2004, 2010 and 2015, respectively. The highest coverage was observed in Bacillus Calmette–Guérin (BCG) and lowest in oral polio vaccine 1 (OPV1). OPV1 coverage was <90% in the 2004 cohort year, while pentavalent 3 (Penta3) and measles-containing vaccine 1 (MCV1) coverages were <90% in 2004. Dropout rates of Penta3 and MCV1 were significantly >10% in 2004. The logistic regression analyses showed that children were significantly less likely to be immunized with Penta3 and MCV1 in all cohort years compared with Penta1. CONCLUSIONS: Although immunization coverage was in line with the national and district targets for various antigens, full vaccination coverage (FVC) is still lagging behind. Furthermore, the dropout rates for Penta3 and MCV1 showed upside U-shaped patterns. Thus health education, supervision and orientation of service providers are urgently needed to address disparities that are existing in FVC.